Hi there ! same problem here ! for years and years...the same problem....as i read here in previous posts regarding the
same issue , when you "create" an iconpack theme from scratch..the problem doesnt happen .
But if you try to modify an existing theme and save creating a new one...It will work , but only partially . The big issue here is if you change the theme and return to the one you modified before ...even noticing that the pack you modified saved the icon images created in the new theme folder , it simply doesnt work !! . So , Sorry you should manually assign all the COntrol Panel ( and the other failed ones ) using the option "apply my changes" but since then they wont change .. . But sorry it will work just until next Theme change !. In case you try to return to this theme....blah....you will have again to make stuff manually again.