MouseOver color exists on KeyBoard traversal of slider thumb in Synth.

Steps to reproduce:
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1) Unzip the attached code.
2) Compile and run SynthSliderTest on b32.
3) Take mouse over the thumb of the slider.
4) Notice that the color of thumb is now blue.
5) Now using arrow key move the thumb without moving the mouse.
6) Notice that the color of the thumb is still blue and not magenta (Focused color)