diff --git a/gui/wxpython/iscatt/plots.py b/gui/wxpython/iscatt/plots.py
index 08996137779..2a3d14341a4 100644
--- a/gui/wxpython/iscatt/plots.py
+++ b/gui/wxpython/iscatt/plots.py
@@ -619,7 +619,8 @@ def ContexMenu(self, event):
     def ShowMenu(self, menu):
         self.plot.PopupMenu(menu)
         menu.Destroy()
-        self.plot.ReleaseMouse()
+        if self.plot.HasCapture():
+            self.plot.ReleaseMouse()
 
 
 class PolygonDrawer: