diff --git a/ui/psmlcols.go b/ui/psmlcols.go
new file mode 100644
index 0000000..4b8a94e
--- /dev/null
+++ b/ui/psmlcols.go
@@ -0,0 +1,323 @@
+// Copyright 2019-2020 Graham Clark. All rights reserved.  Use of this source
+// code is governed by the MIT license that can be found in the LICENSE
+// file.
+
+// Package ui contains user-interface functions and helpers for termshark.
+package ui
+
+import (
+	"reflect"
+	"sort"
+
+	"github.com/gcla/gowid"
+	"github.com/gcla/gowid/widgets/button"
+	"github.com/gcla/gowid/widgets/clicktracker"
+	"github.com/gcla/gowid/widgets/columns"
+	"github.com/gcla/gowid/widgets/dialog"
+	"github.com/gcla/gowid/widgets/divider"
+	"github.com/gcla/gowid/widgets/framed"
+	"github.com/gcla/gowid/widgets/holder"
+	"github.com/gcla/gowid/widgets/hpadding"
+	"github.com/gcla/gowid/widgets/menu"
+	"github.com/gcla/gowid/widgets/null"
+	"github.com/gcla/gowid/widgets/pile"
+	"github.com/gcla/gowid/widgets/styled"
+	"github.com/gcla/gowid/widgets/table"
+	"github.com/gcla/gowid/widgets/text"
+	"github.com/gcla/termshark/v2"
+	"github.com/gcla/termshark/v2/shark"
+	"github.com/gcla/termshark/v2/shark/wiresharkcfg"
+	"github.com/gcla/termshark/v2/ui/menuutil"
+	"github.com/gdamore/tcell"
+)
+
+//======================================================================
+
+var colNamesMenu *menu.Widget
+var colFieldsMenu *menu.Widget
+
+// These are global variables used to hold the current model for the edit-columns
+// widget, and the current line selected. This is hacky but it's so that I can tell,
+// when a menu button is clicked within this PSML columns widget, which column
+// it should apply to. I could generate unique menus for each row of the table, as
+// an alternative...
+var colsCurrentModel *psmlColumnsModel
+var colsCurrentModelRow int
+
+var colNamesMenuListBoxHolder *holder.Widget
+var colFieldsMenuListBoxHolder *holder.Widget
+
+//======================================================================
+
+func buildNamesMenu(app gowid.IApp) {
+	colNamesMenuListBoxHolder = holder.New(null.New())
+
+	wid, hei := rebuildPsmlNamesListBox(colsCurrentModel, app)
+
+	colNamesMenu = menu.New("psmlcols", colNamesMenuListBoxHolder, gowid.RenderWithUnits{U: wid}, menu.Options{
+		Modal:             true,
+		CloseKeysProvided: true,
+		CloseKeys: []gowid.IKey{
+			gowid.MakeKeyExt(tcell.KeyEscape),
+			gowid.MakeKeyExt(tcell.KeyCtrlC),
+		},
+	})
+
+	colNamesMenu.SetHeight(units(hei), app)
+}
+
+func buildFieldsMenu(app gowid.IApp) {
+	colFieldsMenuListBoxHolder = holder.New(null.New())
+
+	wid, hei := rebuildPsmlFieldListBox(app)
+
+	colFieldsMenu = menu.New("psmlfieldscols", colFieldsMenuListBoxHolder, gowid.RenderWithUnits{U: wid}, menu.Options{
+		Modal:             true,
+		CloseKeysProvided: true,
+		CloseKeys: []gowid.IKey{
+			gowid.MakeKeyExt(tcell.KeyEscape),
+			gowid.MakeKeyExt(tcell.KeyCtrlC),
+		},
+	})
+	colFieldsMenu.SetHeight(units(hei), app)
+}
+
+type psmlColumnInfoArraySortLong []shark.PsmlColumnInfo
+
+func (a psmlColumnInfoArraySortLong) Len() int {
+	return len(a)
+}
+func (a psmlColumnInfoArraySortLong) Swap(i, j int) {
+	a[i], a[j] = a[j], a[i]
+}
+func (a psmlColumnInfoArraySortLong) Less(i, j int) bool {
+	return a[i].Long < a[j].Long
+}
+
+// return width needed
+func rebuildPsmlNamesListBox(p *psmlColumnsModel, app gowid.IApp) (int, int) {
+	colsMenuItems := make([]menuutil.SimpleMenuItem, 0)
+
+	specs := make(psmlColumnInfoArraySortLong, 0)
+
+	for _, v := range shark.AllowedColumnFormats {
+		specs = append(specs, v)
+	}
+	sort.Sort(specs)
+
+	for _, spec := range specs {
+		speccopy := spec
+		colsMenuItems = append(colsMenuItems,
+			menuutil.SimpleMenuItem{
+				Txt: spec.Long,
+				CB: func(app gowid.IApp, w gowid.IWidget) {
+					colNamesMenu.Close(app)
+					p.UpdateFromField(speccopy.Field, colsCurrentModelRow)
+					app.Sync()
+				},
+			},
+		)
+	}
+
+	colsMenuListBox, wid := menuutil.MakeMenu(colsMenuItems)
+	colNamesMenuListBoxHolder.SetSubWidget(colsMenuListBox, nil)
+
+	return wid, len(specs)
+}
+
+func rebuildPsmlFieldListBox(app gowid.IApp) (int, int) {
+	p := colsCurrentModel
+
+	colsMenuItems := make([]menuutil.SimpleMenuItem, 0)
+
+	columnNames := make([]string, 0)
+	for k, _ := range shark.AllowedColumnFormats {
+		columnNames = append(columnNames, k)
+	}
+	sort.Strings(columnNames)
+
+	for _, cname := range columnNames {
+		cname2 := cname
+		colsMenuItems = append(colsMenuItems,
+			menuutil.SimpleMenuItem{
+				Txt: cname,
+				CB: func(app gowid.IApp, w gowid.IWidget) {
+					colFieldsMenu.Close(app)
+					p.UpdateFromField(cname2, colsCurrentModelRow)
+					app.Sync()
+				},
+			},
+		)
+	}
+
+	colsMenuListBox, wid := menuutil.MakeMenu(colsMenuItems)
+	colFieldsMenuListBoxHolder.SetSubWidget(colsMenuListBox, nil)
+
+	return wid, len(columnNames)
+}
+
+//======================================================================
+
+func openEditColumns(app gowid.IApp) {
+	pcols := NewPsmlColumnsModel()
+	colsCurrentModel = pcols
+
+	var mainw gowid.IWidget
+
+	newPsmlCol := button.New(text.New("+"))
+	newPsmlCol.OnClick(gowid.MakeWidgetCallback("cb", func(app gowid.IApp, widget gowid.IWidget) {
+		pcols.AddRow()
+	}))
+
+	newPsmlColStyled := hpadding.New(clicktracker.New(
+		styled.NewExt(
+			newPsmlCol,
+			gowid.MakePaletteRef("button"),
+			gowid.MakePaletteRef("button-focus"),
+		),
+	), gowid.HAlignLeft{}, gowid.RenderFixed{})
+
+	colWidgets := make([]interface{}, 0)
+
+	pileWidgets := make([]interface{}, 0)
+	pileWidgets = append(pileWidgets, pcols, divider.NewBlank(), newPsmlColStyled)
+
+	wcfg, err := wiresharkcfg.NewDefault()
+	if err == nil {
+		cols := wcfg.ColumnFormat()
+		if cols != nil {
+			btn := button.New(text.New("Import"))
+			btn.OnClick(gowid.MakeWidgetCallback("cb", func(app gowid.IApp, widget gowid.IWidget) {
+				newPcols := NewPsmlColumnsModel()
+				err = newPcols.ReadFromWireshark()
+				if err != nil {
+					OpenError(err.Error(), app)
+					return
+				}
+
+				*pcols = *newPcols
+				pcols.Widget = table.New(pcols)
+				OpenMessage("Imported column preferences from Wireshark", appView, app)
+			}))
+
+			cols := hpadding.New(
+				columns.NewFixed(
+					clicktracker.New(
+						styled.NewExt(
+							btn,
+							gowid.MakePaletteRef("button"),
+							gowid.MakePaletteRef("button-focus"),
+						),
+					),
+					text.New(" from Wireshark"),
+				),
+				gowid.HAlignLeft{},
+				gowid.RenderFixed{},
+			)
+			colWidgets = append(colWidgets, cols)
+		}
+	}
+
+	bakCols := termshark.ConfStringSlice("main.column-format-bak", []string{})
+	if len(bakCols) != 0 {
+		btn := button.New(text.New("Restore"))
+		btn.OnClick(gowid.MakeWidgetCallback("cb", func(app gowid.IApp, widget gowid.IWidget) {
+			newPcols := NewPsmlColumnsModelFrom("main.column-format-bak")
+			if len(newPcols.spec) == 0 {
+				OpenMessage("Error: backup column-format is empty in toml file", appView, app)
+				return
+			}
+
+			*pcols = *newPcols
+			pcols.Widget = table.New(pcols)
+			OpenMessage("Imported previous column preferences", appView, app)
+		}))
+
+		cols := hpadding.New(
+			columns.NewFixed(
+				clicktracker.New(
+					styled.NewExt(
+						btn,
+						gowid.MakePaletteRef("button"),
+						gowid.MakePaletteRef("button-focus"),
+					),
+				),
+				text.New(" previous columns"),
+			),
+			gowid.HAlignLeft{},
+			gowid.RenderFixed{},
+		)
+		colWidgets = append(colWidgets, cols)
+	}
+
+	restoreBtn := button.New(text.New("Restore"))
+	restoreBtn.OnClick(gowid.MakeWidgetCallback("cb", func(app gowid.IApp, widget gowid.IWidget) {
+		*pcols = *NewDefaultPsmlColumnsModel()
+		pcols.Widget = table.New(pcols)
+		OpenMessage("Imported default column preferences", appView, app)
+	}))
+
+	cols := hpadding.New(
+		columns.NewFixed(
+			clicktracker.New(
+				styled.NewExt(
+					restoreBtn,
+					gowid.MakePaletteRef("button"),
+					gowid.MakePaletteRef("button-focus"),
+				),
+			),
+			text.New(" default columns"),
+		),
+		gowid.HAlignLeft{},
+		gowid.RenderFixed{},
+	)
+
+	colWidgets = append(colWidgets, cols)
+	buttonRow := columns.NewWithDim(gowid.RenderWithWeight{W: 1}, colWidgets...)
+
+	pileWidgets = append(pileWidgets, divider.NewBlank(), buttonRow)
+
+	mainw = pile.NewFlow(pileWidgets...)
+
+	var editColsDialog *dialog.Widget
+
+	okButton := dialog.Button{
+		Msg: "Ok",
+		Action: gowid.WidgetChangedFunction(func(app gowid.IApp, widget gowid.IWidget) {
+			newcols := pcols.ToConfigList()
+			curcols := termshark.ConfStringSlice("main.column-format", []string{})
+
+			if !reflect.DeepEqual(newcols, curcols) {
+				termshark.SetConf("main.column-format-bak", curcols)
+				termshark.SetConf("main.column-format", pcols.ToConfigList())
+			} else {
+				OpenMessage("No change - same columns configured", appView, app)
+			}
+
+			editColsDialog.Close(app)
+
+			RequestReload(app)
+		}),
+	}
+
+	editColsDialog = dialog.New(
+		framed.NewSpace(
+			mainw,
+		),
+		dialog.Options{
+			Buttons:         []dialog.Button{okButton, dialog.Cancel},
+			NoShadow:        true,
+			BackgroundStyle: gowid.MakePaletteRef("dialog"),
+			BorderStyle:     gowid.MakePaletteRef("dialog"),
+			ButtonStyle:     gowid.MakePaletteRef("dialog-button"),
+		},
+	)
+
+	editColsDialog.Open(appView, ratio(0.5), app)
+}
+
+//======================================================================
+// Local Variables:
+// mode: Go
+// fill-column: 110
+// End:
diff --git a/ui/psmlcolsmodel.go b/ui/psmlcolsmodel.go
new file mode 100644
index 0000000..9a739c1
--- /dev/null
+++ b/ui/psmlcolsmodel.go
@@ -0,0 +1,383 @@
+// Copyright 2019-2020 Graham Clark. All rights reserved.  Use of this source
+// code is governed by the MIT license that can be found in the LICENSE
+// file.
+
+// Package ui contains user-interface functions and helpers for termshark.
+package ui
+
+import (
+	"fmt"
+
+	"github.com/gcla/gowid"
+	"github.com/gcla/gowid/widgets/button"
+	"github.com/gcla/gowid/widgets/clicktracker"
+	"github.com/gcla/gowid/widgets/columns"
+	"github.com/gcla/gowid/widgets/edit"
+	"github.com/gcla/gowid/widgets/hpadding"
+	"github.com/gcla/gowid/widgets/menu"
+	"github.com/gcla/gowid/widgets/styled"
+	"github.com/gcla/gowid/widgets/table"
+	"github.com/gcla/gowid/widgets/text"
+	"github.com/gcla/termshark/v2"
+	"github.com/gcla/termshark/v2/shark"
+	"github.com/gcla/termshark/v2/shark/wiresharkcfg"
+)
+
+//======================================================================
+
+var ColumnsFormatError = fmt.Errorf("The supplied list of columns and names is invalid")
+
+// psmlColumnsModel is itself a gowid table widget. This allows me to use the model
+// directly in the widget hierarchy, and has the advantage that if I update the model,
+// I can regenerate the embedded table widget because I have a handle to it. Otherwise
+// I would need to build a more complicated model with callbacks when data changes, and
+// have those callbacks tied to the table displaying the data.
+type psmlColumnsModel struct {
+	spec        []shark.PsmlColumnSpec // the actual rows - field name, long name
+	customNames []*edit.Widget         // save the user-configured name
+	*table.Widget
+}
+
+var _ table.IBoundedModel = (*psmlColumnsModel)(nil)
+var _ table.IInvertible = (*psmlColumnsModel)(nil)
+
+var (
+	left  = gowid.HAlignLeft{}
+	mid   = gowid.HAlignMiddle{}
+	right = gowid.HAlignRight{}
+)
+
+//======================================================================
+
+func NewDefaultPsmlColumnsModel() *psmlColumnsModel {
+	spec := shark.DefaultPsmlColumnSpec
+	// copy it to protect from alterations
+	specCopy := make([]shark.PsmlColumnSpec, len(spec))
+	for i := 0; i < len(spec); i++ {
+		specCopy[i] = spec[i]
+	}
+	res := &psmlColumnsModel{
+		spec: specCopy,
+	}
+	res.fixup()
+	return res
+}
+
+func NewPsmlColumnsModel() *psmlColumnsModel {
+	spec := shark.GetPsmlColumnFormat()
+	res := &psmlColumnsModel{
+		spec: spec,
+	}
+	res.fixup()
+	return res
+}
+
+func NewPsmlColumnsModelFrom(key string) *psmlColumnsModel {
+	spec := shark.GetPsmlColumnFormatFrom(key)
+	res := &psmlColumnsModel{
+		spec: spec,
+	}
+	res.fixup()
+	return res
+}
+
+func (p *psmlColumnsModel) String() string {
+	return fmt.Sprintf("%v", p.spec)
+}
+
+func (p *psmlColumnsModel) ToConfigList() []string {
+	res := make([]string, 0, len(p.spec))
+	for i := 0; i < len(p.spec); i++ {
+		custom := p.customNames[i].Text()
+		if custom == "" {
+			res = append(res, p.spec[i].Field)
+		} else {
+			res = append(res, fmt.Sprintf("%s %s", p.spec[i].Field, custom))
+		}
+	}
+	return res
+}
+
+func (p *psmlColumnsModel) AddRow() {
+	p.spec = append(p.spec, shark.PsmlColumnSpec{Field: "%m", Name: "No."})
+	p.customNames = append(p.customNames, edit.New(edit.Options{
+		Text: p.spec[len(p.spec)-1].Name,
+	}))
+}
+
+// Make rest of data structure consistent with recent changes
+func (p *psmlColumnsModel) fixup() {
+	cnames := make([]*edit.Widget, len(p.spec))
+	for i := 0; i < len(cnames); i++ {
+		cnames[i] = edit.New(edit.Options{
+			Text: p.spec[i].Name,
+		})
+	}
+	p.customNames = cnames
+	p.Widget = table.New(p)
+}
+
+func stripQuotes(s string) string {
+	if len(s) > 0 && s[0] == '"' {
+		s = s[1:]
+	}
+	if len(s) > 0 && s[len(s)-1] == '"' {
+		s = s[:len(s)-1]
+	}
+	return s
+}
+
+func (p *psmlColumnsModel) ReadFromWireshark() error {
+	wcfg, err := wiresharkcfg.NewDefault()
+	if err != nil {
+		return err
+	}
+
+	wcols := wcfg.ColumnFormat()
+	if wcols == nil {
+		return fmt.Errorf("Could not read Wireshark column preferences")
+	}
+
+	if (len(wcols)/2)*2 != len(wcols) {
+		return gowid.WithKVs(ColumnsFormatError, map[string]interface{}{
+			"columns": wcols,
+		})
+	}
+
+	specs := make([]shark.PsmlColumnSpec, 0)
+	for i := 0; i < len(wcols); i += 2 {
+		specs = append(specs, shark.PsmlColumnSpec{
+			Field: stripQuotes(wcols[i+1]),
+			Name:  stripQuotes(wcols[i]),
+		})
+	}
+
+	p.spec = specs
+	p.fixup()
+	return nil
+}
+
+func (p *psmlColumnsModel) UpdateFromField(field string, idx int) {
+	p.spec[idx].Field = field
+	p.spec[idx].Name = shark.AllowedColumnFormats[field].Long
+
+	p.Widget = table.New(p)
+}
+
+func (p *psmlColumnsModel) UpdateFromField2(field string, idx int) {
+	p.spec[idx].Field = field
+	p.spec[idx].Name = shark.AllowedColumnFormats[field].Long
+
+	p.Widget = table.New(p)
+}
+
+// WriteToConfig writes the PSML column model to the termshark toml
+func (m *psmlColumnsModel) WriteToConfig() {
+	tcols := make([]string, 0)
+	for _, v := range m.spec {
+		tcols = append(tcols, fmt.Sprintf("%s %s", v.Field, v.Name))
+	}
+	termshark.SetConf("main.column-format", tcols)
+}
+
+func (m *psmlColumnsModel) moveDown(row int, app gowid.IApp) {
+	i := row
+	j := row + 1
+
+	m.spec[i], m.spec[j] = m.spec[j], m.spec[i]
+	m.customNames[i], m.customNames[j] = m.customNames[j], m.customNames[i]
+
+	m.Widget = table.New(m)
+}
+
+func (m *psmlColumnsModel) moveUp(row int, app gowid.IApp) {
+	i := row
+	j := row - 1
+
+	m.spec[i], m.spec[j] = m.spec[j], m.spec[i]
+	m.customNames[i], m.customNames[j] = m.customNames[j], m.customNames[i]
+
+	m.Widget = table.New(m)
+}
+
+// row is the screen position
+func (m *psmlColumnsModel) deleteRow(trow table.RowId, app gowid.IApp) {
+	row := int(trow)
+	m.spec = append(m.spec[:row], m.spec[row+1:]...)
+	m.customNames = append(m.customNames[:row], m.customNames[row+1:]...)
+
+	m.Widget = table.New(m)
+}
+
+// construct the widgets for each row in the dialog used to configure PSML
+// columns.
+func (p *psmlColumnsModel) CellWidgets(row table.RowId) []gowid.IWidget {
+	rowi := int(row)
+
+	res := make([]gowid.IWidget, 0)
+
+	pad := func(w gowid.IWidget, pos gowid.IHAlignment, r int, fn func(int) gowid.WidgetChangedFunction) gowid.IWidget {
+		btn := button.NewAlt(w)
+		btn.OnClick(gowid.MakeWidgetCallback(gowid.ClickCB{}, fn(r)))
+
+		return hpadding.New(
+			clicktracker.New(
+				styled.NewExt(
+					btn,
+					gowid.MakePaletteRef("dialog"),
+					gowid.MakePaletteRef("dialog-button"),
+				),
+			),
+			pos,
+			gowid.RenderFixed{},
+		)
+	}
+
+	colsMenuFieldsSite := menu.NewSite(menu.SiteOptions{YOffset: 1})
+	// Field name
+	colsMenuFieldsButton := button.NewBare(text.New(p.spec[rowi].Field))
+	colsMenuFieldsButton.OnClick(gowid.MakeWidgetCallback(gowid.ClickCB{}, func(app gowid.IApp, target gowid.IWidget) {
+		wid, hei := rebuildPsmlFieldListBox(app)
+		colsCurrentModelRow = rowi
+		colFieldsMenu.SetWidth(units(wid), app)
+		colFieldsMenu.SetHeight(units(hei), app)
+		colFieldsMenu.Open(colsMenuFieldsSite, app)
+	}))
+
+	if rowi == 0 {
+		res = append(res, nullw)
+	} else {
+		res = append(res, pad(text.New("^"), left, rowi, func(r int) gowid.WidgetChangedFunction {
+			return func(app gowid.IApp, target gowid.IWidget) {
+				p.moveUp(r, app)
+			}
+		}))
+	}
+
+	if rowi == len(p.spec)-1 {
+		res = append(res, nullw)
+	} else {
+		res = append(res, pad(text.New("v"), left, rowi, func(r int) gowid.WidgetChangedFunction {
+			return func(app gowid.IApp, target gowid.IWidget) {
+				p.moveDown(r, app)
+			}
+		}))
+	}
+	res = append(res,
+		columns.NewFixed(
+			colsMenuFieldsSite,
+			clicktracker.New(
+				styled.NewExt(
+					colsMenuFieldsButton,
+					gowid.MakePaletteRef("button"),
+					gowid.MakePaletteRef("button-focus"),
+				),
+			),
+		),
+	)
+	res = append(res, p.customNames[row])
+
+	colsMenuSite := menu.NewSite(menu.SiteOptions{YOffset: 1})
+	colsMenuButton := button.NewBare(text.New(shark.AllowedColumnFormats[p.spec[row].Field].Long))
+	colsMenuButton.OnClick(gowid.MakeWidgetCallback(gowid.ClickCB{}, func(app gowid.IApp, target gowid.IWidget) {
+		wid, hei := rebuildPsmlNamesListBox(p, app)
+		colsCurrentModelRow = rowi
+		colNamesMenu.SetWidth(units(wid), app)
+		colNamesMenu.SetHeight(units(hei), app)
+		colNamesMenu.Open(colsMenuSite, app)
+	}))
+
+	res = append(res,
+		columns.NewFixed(
+			colsMenuSite,
+			clicktracker.New(
+				styled.NewExt(
+					colsMenuButton,
+					gowid.MakePaletteRef("button"),
+					gowid.MakePaletteRef("button-focus"),
+				),
+			),
+		),
+	)
+
+	if len(p.spec) <= 1 {
+		res = append(res, nullw)
+	} else {
+		res = append(res, pad(text.New("X"), mid, rowi, func(r int) gowid.WidgetChangedFunction {
+			return func(app gowid.IApp, target gowid.IWidget) {
+				p.deleteRow(row, app)
+			}
+		}))
+	}
+
+	return res
+}
+
+func (p *psmlColumnsModel) Columns() int {
+	return 6
+}
+
+func (p *psmlColumnsModel) Widths() []gowid.IWidgetDimension {
+	return []gowid.IWidgetDimension{
+		gowid.RenderWithUnits{U: 3},
+		gowid.RenderWithUnits{U: 4},
+		gowid.RenderWithWeight{W: 1},
+		gowid.RenderWithWeight{W: 1},
+		gowid.RenderWithWeight{W: 1},
+		gowid.RenderWithUnits{U: 9},
+	}
+}
+
+func (p *psmlColumnsModel) Rows() int {
+	return len(p.spec)
+}
+
+func (p *psmlColumnsModel) HorizontalSeparator() gowid.IWidget {
+	return nil
+}
+
+func (p *psmlColumnsModel) HeaderSeparator() gowid.IWidget {
+	return nil
+}
+
+func (p *psmlColumnsModel) HeaderWidgets() []gowid.IWidget {
+
+	pr := gowid.MakePaletteRef("dialog")
+	st := func(w gowid.IWidget) gowid.IWidget {
+		return styled.NewExt(w, gowid.ColorInverter{pr}, gowid.ColorInverter{pr})
+	}
+
+	return []gowid.IWidget{
+		st(text.New("")),
+		st(text.New(" ")),
+		st(text.New("  Field ")),
+		st(text.New("  Custom ")),
+		st(text.New("  Name ")),
+		st(text.New("  Remove ")),
+	}
+}
+
+func (p *psmlColumnsModel) VerticalSeparator() gowid.IWidget {
+	return nil
+}
+
+func (p *psmlColumnsModel) RowIdentifier(row int) (table.RowId, bool) {
+	if row < 0 || row >= len(p.spec) {
+		return -1, false
+	}
+	return table.RowId(row), true
+}
+
+func (p *psmlColumnsModel) IdentifierToRow(rowid table.RowId) (int, bool) {
+	if rowid < 0 || int(rowid) >= len(p.spec) {
+		return -1, false
+	} else {
+		return int(rowid), true
+	}
+}
+
+//======================================================================
+// Local Variables:
+// mode: Go
+// fill-column: 110
+// End: