git gui: keep selected branch when remote is changed in push dialog
The selection of the branch to be pushed would be cleared when the remote was changed. This seems to be dependent on the fact that the selected content in the combobox was exported to the clipboard. It was only apparent when using the new ttk widget.
Signed-off-by: Heiko Voigt <firstname.lastname@example.org> Signed-off-by: Pat Thoyts <email@example.com>