Code review comment for lp:~larsu/overlay-scrollbar/fix-for-3.10

Setting transient window is required at least for gtk2.
If you leave a window unfocused and click on its scrollbar, the window won't get focused without that.

The changes to use parent window kinda worries me for old Gtk too, but so far I didn't find bugs.

I saw you moved some bits in the realize function, but I think you still want to keep the old order... because you need to have events activated before adding the filter or it won't work.

Is setting the user data of the gdkwindow required in gtk2?