Tk Source Code

With a dual monitor setup, a window in the second display, changed to fullscreen mode will go to fullscreen in the first display rather than the second.   I tested this on Windows Vista and VirtualBox/Windows 7.


#!/usr/bin/tclsh

package require Tk

proc toggleFullscreen { } {
   set fs [wm attribute .win2 -fullscreen]
   wm attribute .win2 -fullscreen [expr {1-$fs}]
}

toplevel .win2
bind .win2 <Double-1> toggleFullscreen
ttk::label .lab1 -text {Window 1}
pack .lab1 -in .
ttk::label .win2.lab2 -text {Window 2}
pack .win2.lab2 -in .win2

Many thanks, Serhiy! Merged into main, core-9-0-branch, and core-8-6-branch by commits [52a9c119], [c30bc468], and [5a3ac179].

UpdateWrapper (win/tkWinWm.c) always used the origin and size of the primary screen for full screen mode.

Proposed fix in branch win-fullscreen-monitor: use the monitor nearest the window (MonitorFromRect, GetMonitorInfo). Tested on Windows 11 with two monitors: a normal, zoomed or not yet mapped window on the second monitor now goes full screen on the second monitor, and returns to its previous geometry or zoomed state there.

[106af72ae0] is a duplicate.

Confirmed it works OK on Debian 8 with two monitors. Double-clicking inside window 2 toggles fullscreen on the monitor where the window is displayed.

Looks like the WM understands there is a single screen displayed on two monitors. (this remark in link with the discussion around [c95d4691ff]).

This is not a problem on Linux.
The windows changes to fullscreen on the correct monitor.

I am unable to test on Mac OS X -- I only have a single monitor there.

Works on FreeBSD (mate desktop)-- tested just now.

Looks like it's hardcoded for MacOSX as well but I'm not sure.

Again:

Could someone please confirm whether this problem exists on Mac and on Linux, or not?

This appears to be hardcoded in Tk, at least for Windows.

Could someone please confirm whether this problem exists on Mac and on Linux, or not?

Confirmed on Win 8.1 with a Laptop with an external Monitor.
Fullscreen always on the Primary screen, even if normal window on the extended screen.