Common control version 6 is AFAIK used to create transparency.
It has a function for it that K-Meleon uses.
This is not available in Win98/Win2000 and some Linux wine versions.
And on newer systems when the version 6 is not installed, broken or if the application's manifest file does not ask for it so that it is not used - no matter whether it is there.
K-Meleon prior to 1.5.4/1.6 have less or no transparency support.
Some throbber.avi have no transparent colour. You can create a throbber with black background.
No idea whether some Windows settings make the transparent black -> black again.
The default throbber should look like this.
Well it does on my system.
p.s. To answer such a question with certainty we need much more info about Your system, K-Meleon version, skin and throbber.
Edited 3 time(s). Last edit at 01/21/2015 08:42PM by guenter.