FvwmIconMan lists wrong windows in (certain?) multi-monitor configurations.

[jnse]

Upfront Information

~> fvwm3 --version
fvwm3 1.0.3 (620cf578)
with support for:  ReadLine, XPM, PNG, SVG, Shape, XShm, SM, Bidi text, XRandR, XRender, XCursor, XFT, NLS

~> uname -a
Linux slate 5.9.14-gentoo-x86_64 #1 SMP Fri Dec 11 19:05:04 CST 2020 x86_64 AMD Ryzen 9 3950X 16-Core Processor AuthenticAMD GNU/Linux

~> uname -sp
Linux AMD Ryzen 9 3950X 16-Core Processor

Expected Behaviour

*FvwmIconMan: Resolution screen

Should only show windows for the monitor the IconMan is hosted on.

*FvwmIconMan: Resolution desktop

Should always show all windows on the current desktop.

Actual Behaviour

Resolution screen shows windows on monitors other than the monitor hosting the FvwmIconMan.

Resolution desktop does not always show all windows on all monitors in the current desktop.

Debug Log

[1608763386.911619]  log opened (because of SIGUSR2)
[1608763391.101561] ewmh_ComputeAndSetWorkArea: monitor 'DP-4': {l: 0, r: 0, t: 0, b: 66} {x: 0, y: 0, w: 2944, h: 1914}
[1608763396.515267] monitor_dump_state: Monitor Debug
[1608763396.515284] monitor_dump_state: 	number of outputs: 4
[1608763396.515292] monitor_dump_state: 	Name:	DP-2
	Disabled:	false
	Is Primary:	yes
	Is Current:	no
	Output:	550
	Coords:	{x: 1920, y: 132, w: 1024, h: 768}
	VirtScr: {
		VxMax: 0, VyMax: 0, Vx: 0, Vy: 0
		EdgeScrollX: 0, EdgeScrollY: 0
		CurrentDesk: 0
		CurrentPage: {x: 0, y: 0}
		MyDisplayWidth: 2944, MyDisplayHeight: 1980
	}
	Desktops:	yes
	Flags:global

[1608763396.515297] monitor_dump_state: 	Name:	DP-1
	Disabled:	false
	Is Primary:	no
	Is Current:	no
	Output:	446
	Coords:	{x: 320, y: 0, w: 1600, h: 900}
	VirtScr: {
		VxMax: 0, VyMax: 0, Vx: 0, Vy: 0
		EdgeScrollX: 0, EdgeScrollY: 0
		CurrentDesk: 0
		CurrentPage: {x: 0, y: 0}
		MyDisplayWidth: 2944, MyDisplayHeight: 1980
	}
	Desktops:	yes
	Flags:global

[1608763396.515302] monitor_dump_state: 	Name:	HDMI-0
	Disabled:	false
	Is Primary:	no
	Is Current:	no
	Output:	529
	Coords:	{x: 0, y: 900, w: 1920, h: 1080}
	VirtScr: {
		VxMax: 0, VyMax: 0, Vx: 0, Vy: 0
		EdgeScrollX: 0, EdgeScrollY: 0
		CurrentDesk: 0
		CurrentPage: {x: 0, y: 0}
		MyDisplayWidth: 2944, MyDisplayHeight: 1980
	}
	Desktops:	yes
	Flags:global

[1608763396.515306] monitor_dump_state: 	Name:	DP-4
	Disabled:	false
	Is Primary:	no
	Is Current:	yes
	Output:	552
	Coords:	{x: 1920, y: 900, w: 1024, h: 768}
	VirtScr: {
		VxMax: 0, VyMax: 0, Vx: 0, Vy: 0
		EdgeScrollX: 0, EdgeScrollY: 0
		CurrentDesk: 0
		CurrentPage: {x: 0, y: 0}
		MyDisplayWidth: 2944, MyDisplayHeight: 1980
	}
	Desktops:	yes
	Flags:global

[1608763406.192146] ewmh_ComputeAndSetWorkArea: monitor 'HDMI-0': {l: 0, r: 0, t: 0, b: 66} {x: 0, y: 0, w: 2944, h: 1914}
[1608763406.226330] ewmh_ComputeAndSetWorkArea: monitor 'HDMI-0': {l: 0, r: 0, t: 0, b: 66} {x: 0, y: 0, w: 2944, h: 1914}
[1608763406.364054] setup_window_placement: Expanding screen from 'null' -> ''
[1608763406.364087] ewmh_ComputeAndSetWorkArea: monitor 'DP-2': {l: 0, r: 0, t: 0, b: 66} {x: 0, y: 0, w: 2944, h: 1914}
[1608763406.364092] EWMH_GetWorkAreaIntersection: mon: DP-2 {ax: 0, ay: 0, aw: 2944, ah: 1914
[1608763406.364096] EWMH_GetWorkAreaIntersection: mon: DP-2 {x: 0, y: 900, w: 1920, h: 1080
[1608763406.364099] EWMH_GetWorkAreaIntersection: mon: DP-2 finalising: {x: 0, y: 900, w: 1920, h: 1014}

display layout: http://www.linkerror.com/stuff/display-layout.png

[ThomasAdam]

Fixed via #396