Hi Dariusz:
[C:\USR\LIB\FIREFOX-45.9.0]highmem -vv xul.dll
Processing module : xul.dll
object 0 : base 0x00010000, size 0x0291b780, flags 0x00002005, executable, !him
em
readable, !writeable, executable, !resource, !discardable, !shared,
!preload, !invalid, swappable, !16:16 alias, !conforming,
32bit, !IOPL
object 1 : base 0x02930000, size 0x00079cb0, flags 0x00002003, data, !himem
readable, writeable, !executable, !resource, !discardable, !shared,
!preload, !invalid, swappable, !16:16 alias, !conforming,
32bit, !IOPL
object 2 : base 0x00000000, size 0x00002324, flags 0x00002039, data, !himem
readable, !writeable, !executable, resource, discardable, shared,
!preload, !invalid, swappable, !16:16 alias, !conforming,
32bit, !IOPL
but no change about the described situation.
Then also given the command highmem.exe -c xul.dll with same negative answer.
All this tried before running FF first time. Tried with FF already running, in this case "unlock xul.dll" result is positive:" xul.dll UNLOCKED", but with no success for the purpose to have Firefox and Staroffice running meantime.
If Firefox is running, then Staroffice Writer just won't load, if Staroffice Writer is running then Firefox won't load, with this message instead : "Couldn't load xul.dll (OS2 error 8 faulty module : C:\USR\LIB\FIREFOX-45.9.0\XUL.DLL)"