Creating even the simplest of levels I get this after previewing the game.
I have tested it in Firefox and Chrome. Same results.
Makes it pretty unusable for editing. Any ideas?
Yeah, it’s related to WebGL (you can try to disable it), here is the discussion:
http://www.forum.compilgames.net/viewtopic.php?f=45&t=5892
Note that this is the GDevelop section, the GDevApp section is some pixels below 
Thanks.
Disabled WebGL. The only rainbows I see now are outside 
(thanks for the pointer to the right forum too. All I saw was ‘bug reports’ and posted without looking further)
Hm, maybe we should restructurize forum if this will be issue with more users? Like following tree:
Bug reports
|-GDevelop
|-GDevApp
Feature requests
|-GDevelop
|-GDevApp
Of course there’s no sense of doing this for one user, but if more people will have troubles with finding right section, it would be worth considering.
Just to add to the problem description, I tested if the problem would exist on a desktop machine as opposed to the laptops I was using. I was thinking it might just be a limitation of the onboard video vs dedicated video.
The problem reproduced on both mobile and desktop graphics. Hope that aids with the trouble shooting.
In the mean time I’ll continue to use the chrome:// switch fix.
Thanks again.
Thanks again for the follow up! I try to find what’s going on 
It seems to be OK on Firefox (with WebGL on in about:config) so it may be problem with the way WebGL is implemented in Chrome.
Regarding Firefox, I’ve just experienced the problem in Firefox now too unfortunately.