fix updating default viewer menu on change in link type

generalization still needs to be made for the multi-viewer case

jdaviz/components/viewer_data_select_item.vue

@@ -28,7 +28,7 @@
         </v-btn>
       </j-tooltip>
     </div>
-    <div v-else-if="item.has_wcs">
+    <div v-else-if="!linkedByWcs() || item.has_wcs">
       <j-tooltip tipid="viewer-data-enable">
         <v-btn
           icon

jdaviz/configs/imviz/helper.py

@@ -505,6 +505,9 @@ def link_image_data(app, link_type='pixels', wcs_fallback_scheme=None, wcs_use_a
         Invalid inputs or reference data.
 
     """
+    # to avoid any confusion with the capitalized-versions in the links control plugin, let's
+    # just always compare against lowercase here.
+    link_type = link_type.lower()
     if len(app.data_collection) <= 1 and link_type != 'wcs':  # No need to link, we are done.
         return
 
@@ -653,10 +656,13 @@ def link_image_data(app, link_type='pixels', wcs_fallback_scheme=None, wcs_use_a
 
     app._link_type = link_type
     app._wcs_use_affine = wcs_use_affine
+    # TODO: this all needs to be generalized to work on multiple viewers
+    # (including determining refdata)
     viewer_ref = app._jdaviz_helper.default_viewer.reference
     viewer_item = app._get_viewer_item(viewer_ref)
 
     viewer_item['reference_data_label'] = refdata.label
+    viewer_item['linked_by_wcs'] = link_type == 'wcs'
 
     if link_plugin is not None:
         # Only broadcast after success.