gtk_entry_grab_focus in gtkentry.c does not check if the GtkEntry already has a
region of text selected and blindly resets the selection to be all text.

For example in my app a GtkEntry is updated to contain a filename, with all but
the extension selected with gtk_editable_select_region. But when the user tabs
the focus to the entry the act of placing the focus on the entry then selects
all the text.

To reproduce in gtk-demo, open the clipboard dialog and type some text into the
first entry. Then use shift+arrows to select _some_ of the text. Now press tab
to cycle the focus back around to that entry - notice your selection is now lost.


Yes, I know about 'gtk-entry-select-on-focus', but an existing selection should
not be lost regardless of this (user) setting.


I propose the 'selection of all text upon focus' behavior should only occur if
there is no existing selection.