I was adding a feature to the midiChords VST that thepiz.org created (http://www.thepiz.org/plugins/?p=midiChords) and discovered a bug with the label widget. If the label widget is set to editable and is embedded in a pop-up menu, you can’t edit the text. No keyboard interaction occurs, even though you can select the text, right-click and delete it(among other menu items), etc.
This was confirmed by looking at the code for when the plugin is in Guitar View mode:
press the view button, the setup button becomes active
press the setup button, a popup menu appears with a submenu "customize"
select the submenu, and a bunch of sliders with textfields on their left appear
those sliders were created with:
stringSlider[i]->setTextBoxStyle(Slider::TextBoxLeft, false, 80, 20);
so they should be editable, according to the 2nd parameter
void Slider::setTextBoxStyle ( TextEntryBoxPosition newPosition, bool isReadOnly, int textEntryBoxWidth, int textEntryBoxHeight )