OK, minimal code showing the problem (for me, Win XP Sp3, NVidia graphics (GeForce GT710))
(I will test on other computers I have access to and add here)
1) LB 4.5.1 on same machine. It looks like initial picture has buttonface color instead of white! (it was white exactly once, 1st run)
.. But that buttonface changes to backcolor used then obscured, so bug still here
.. (but if initially it not white, "Fill white" just asks to be used anyway)
2) while I still on that machine, JB 1.01 and JB 2 works the same on this program
3) on a virtual Win2000 over same XP
.. JB 1.01 and LB 4.04 works the same, no buttonface color (did I just found regression in LB 4.5.1 ?)
4) Windows 10 32-bit, netbook, Intel graphics
.. Obscuring window does not changes BG. But resizing (or maximizing, or minimizing/restoring) - do change
.. (and "fill white" prevents that)
5) Windows 7, same old computer NVidia graphics (GeForce GT710))
.. JB 2 behaves like in Win10
.. LB 4.5.1 behaves the same (obscuring window not enough, resizing changes color)
.. BUT first run fills bg white, consequent runs - buttonface
Does not need any wavs playing
Needs:
* graphicbox (don't happen in graphic window!)
* changing backcolor (so you see the difference) - for filled figure or for text
... (it will work even without drawing, but empty half-filled window is boring)
* FILL command not used
Instructions:
Run the code.
Move window so it is divided by half by JB IDE.
Click on JB ide, obscuring part of window.
Click on window bringing it to the top.
...Ta-da! Half of window background is changed to whatever background you last set (to your filled figure)
How to fix: why, add "fill white" before drawing
'minimal background bug test
'does not happen in graphicwindow - needs dedicated graphibox
nomainwin
graphicbox #main.g, 5 , 5 , 300 , 300
open "BG bug test" for window as #main
#main, "trapclose [quit]"
#main.g "down"
'now this line FIXES that if uncommented
' #main.g "fill white"
#main.g "home"
#main.g "color red; backcolor cyan; size 5"
'manifests with boxfilled and circlefilled alike. Even without drawing at all
#main.g "home; circlefilled 50"
'#main.g "home; boxfilled 200 200"
#main.g "flush"
wait
'---------------------
[quit]
timer 0
close #main
end