Thank you reporting the issues.
Actually there are some glitches in our buttons. As you already mentioned the look of the button do not repair after enabling happens. The other unfinished part is the IsChecked state - when the button (toggle, radio, split) is checked and disabled the look is pretty sharp like in an enabled control. However regardless these visual glitches buttons should function correct.
PS: According your report we updated your Telerik points.
All the best,
the Telerik team
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