When you tab through fields in the inspector the section headings are included in the cycle.

The problem is that there is no visual confirmation of this happening so it looks like the tabbing has stopped working.

Let's change the 1 pixel border of the section heading to our highlight colour when it has keyboard focus.

I would also like to add the use of the right / left arrow keys to open / close the section when the heading has keyboard focus (we can keep the return key toggle which also does the same thing). This will bring it in line with Library and Layers which already allow the user to press the right / left arrows to open / close.