How do I implement/support/handle this in my own widget derived from Ctrl?
Cannot find how it's done in uppsrc - must be searching for wrong keywords..
found "GetSelectionData()" and overrode in my widget but it is never called
According to info on web X11 uses PRIMARY for this (CLIPBOARD for normal cut&paste)
and I found mention of this in uppsrc:gdkselection.h:GDK_SELECTION_PRIMARY
but not how to make use of it