Continuing my research about issues that cause a blank screen on “Theme editor”, there are some icons which the names are too long. The error is caused when the Style Sheets are generated.
The files that cause this issue are:
The files previously mentioned can be found usually on the following folder:
These images are not being used anymore from portal 6.40, so the solution for this case is remove these files physically.
Check also the note: 1358665