Tabwin buttons are clickable

Signed-off-by: Simon Steinbeiss <simon.steinbeiss@elfenbeinturm.at>
Select window button on mouse over

When the mouse goes over a window button in the tabwin, give that
window button the focus and select it. This way the mouse functions
the same way as the keyboard. When the user clicks on a window
button, focus and raise that winodw and get rid of the tabwin.

Signed-off-by: Simon Steinbeiss <simon.steinbeiss@elfenbeinturm.at>
Don't select the window when it gets mouse focus

Instead of selecting the window, just update the labels in the
tabwin window when the window icon gets the focus. If the user
clicks on the window icon then the widget the mouse is hovering
over will be selected and the tabwin window will disappear.

Signed-off-by: Simon Steinbeiss <simon.steinbeiss@elfenbeinturm.at>