The clip below illustrates the issue. Note, how after the color picker dialog is closed no hover effect gets triggered across the UI. Clicking once in the Rhino window brings back the focus.
I tried parenting the color picker to my drawable-derived crass, the panel its hosted on, and the ActiveDoc, none of these work. Adding SetFocusToMainWindow() after the color picker is closed doesn’t work either.
var color = new Rhino.Display.Color4f(255);
Rhino.UI.Dialogs.ShowColorDialog(Rhino.RhinoDoc.ActiveDoc, ref color, true);
Rhino.RhinoApp.SetFocusToMainWindow();
EDIT: This happens with all modal dialog boxes, not only the color picker. Modeless work fine. A good example is the About dialog:
Rhino.UI.Dialogs.ShowAboutDialog(true); // modeless -> works without issues
Rhino.UI.Dialogs.ShowAboutDialog(false); // modal -> steals focus
I’ll probably need code to a simple example, that I can run here, that reproduces the problem. I’ve not been able to repeat what your reporting - sorry.