Maximize broken when dual monitors are arranged with vertical offset

[kernam]

Upfront Information

• Fvwm3 version:
  fvwm3 1.1.0 (released) with support for: ReadLine, XPM, PNG, SVG, Shape, XShm, SM, Bidi text, XRandR, XRender, XCursor, XFT, NLS

• Linux distribution or BSD name/version
  Debian 12.0

• Platform (run: uname -sp)
  Linux unknown

Expected Behaviour

When using maximize on a window it should take up all available space within the working area.

Actual Behaviour

On one monitor maximize works as expected. On the other monitor the window stretches out in horizontal direction but vertically it only stretches to 81 instead of 1031 (See attached screen shot.)

Enabling logging

Logfile during startup of fvwm3:

[1719382918.069992] FScreenInit: Using RandR
[1719382918.655986] scan_screens: Case 1: Add new monitors
[1719382918.656323] monitor_mark_new: Added new monitor: DP-2-1 (0x55c574ecf0e0)
[1719382918.656387] monitor_mark_new: Added new monitor: DP-2-2 (0x55c574ecf2b0)
[1719382918.821716] main: Loading window states via (null)
[1719382919.304063] ParseBinding: Got mouse button 9 when the maximum is 5.
You can't bind complex functions to this button. To suppress this warning, use:
Silent Mouse 9 A N IceToggleMonitor
[1719382973.970733] is_pan_frame: Window is PanFrame right
[1719382974.430467] is_pan_frame: Window is PanFrame right
[1719383007.438014] monitor_dump_state: Monitor Debug
[1719383007.438134] monitor_dump_state: number of outputs: 2
[1719383007.438265] monitor_dump_state: Number: 0

When sending BugOpts DebugRandR True via FvwmConsole:
[1719383007.438014] monitor_dump_state: Monitor Debug
[1719383007.438134] monitor_dump_state: number of outputs: 2
[1719383007.438265] monitor_dump_state: Number: 0
Name: DP-2-1
Disabled: false
Is Primary: yes
Is Current: yes
Is Previous: no
Output: 70
Coords: {x: 0, y: 0, w: 1920, h: 1080}
VirtScr: {
VxMax: 7680, VyMax: 4320, Vx: 0, Vy: 0
EdgeScrollX: 3840, EdgeScrollY: 2160
CurrentDesk: 0
CurrentPage: {x: 0, y: 0}
MyDisplayWidth: 3840, MyDisplayHeight: 2160
}
EWMH: {
BaseStrut Top: 0
BaseStrut Bottom: 0
BaseStrut Left: 0
BaseStrut Right: 120
}
Desktops: yes
Flags:per-monitor

[1719383007.438537] monitor_dump_state: Number: 1
Name: DP-2-2
Disabled: false
Is Primary: no
Is Current: no
Is Previous: no
Output: 71
Coords: {x: 1920, y: 1080, w: 1920, h: 1080}
VirtScr: {
VxMax: 7680, VyMax: 4320, Vx: 0, Vy: 0
EdgeScrollX: 3840, EdgeScrollY: 2160
CurrentDesk: 0
CurrentPage: {x: 0, y: 0}
MyDisplayWidth: 3840, MyDisplayHeight: 2160
}
EWMH: {
BaseStrut Top: 0
BaseStrut Bottom: 0
BaseStrut Left: 320
BaseStrut Right: 0
}
Desktops: yes
Flags:per-monitor

Steps to Reproduce

xrandr --output DP-2-1 --primary --mode 1920x1080 --pos 0x0 --rotate normal --output DP-2-2 --mode 1920x1080 --pos 1920x1080 --rotate normal

Extra Information

fvwm3-output.log

[kernam]

Sorry for the fuzz. After eliminating the surrounding mate-session, the problem disappeared.