After installing IceWM and manually running icewm-session, I see a bunch of Out Of Memory errors. I've tried switching themes to all those included, as well as a few custom downloaded themes, all with the same result.
I saved off my prior TC builds and was not able to recreate this in 6.4, 8, 10.1 or 12.0
icewm-session: using /home/tc/.icewm for private configuration files
IceWM: using /home/tc/.icewm for private configuration files
icewmtray: using /home/tc/.icewm for private configuration files
icewmbg: using /home/tc/.icewm for private configuration files
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/closeI.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/maximizeI.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/minimizeI.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/restoreI.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/closeA.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/maximizeA.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/minimizeA.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/restoreA.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/closeO.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/maximizeO.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/minimizeO.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/restoreO.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/titleIT.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/titleIB.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/titleAT.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/titleAB.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/menuButtonI.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/menuButtonA.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/themes/icedesert/menuButtonO.xpm
IceWM: Warning: Out of memory for image: /usr/local/share/icewm/taskbar/start.xpm
IceWM: Warning: Out of memory for image: /usr/local/share/icewm/taskbar/windows.xpm
IceWM: Warning: Out of memory for image: /usr/local/share/icewm/taskbar/desktop.xpm
IceWM: Warning: Out of memory for image: /usr/local/share/icewm/taskbar/collapse.xpm
IceWM: Warning: Out of memory for image: /usr/local/share/icewm/taskbar/expand.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/mailbox/mail.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/mailbox/nomail.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/mailbox/errmail.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/mailbox/unreadmail.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/mailbox/newmail.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n0.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n1.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n2.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n3.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n4.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n5.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n6.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n7.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n8.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/n9.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/space.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/colon.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/slash.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/dot.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/a.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/p.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/m.xpm
IceWM: Warning: Out of memory for image /usr/local/share/icewm/ledclock/percent.xpm
IceWM: Warning: Out of memory for pixmap "/usr/local/share/icewm/icons/xterm_16x16.xpm"
IceWM: Warning: Out of memory for pixmap "/usr/local/share/icewm/icons/xterm_32x32.xpm"
IceWM: Warning: Out of memory for pixmap "/usr/local/share/icewm/icons/xterm_32x32.xpm"