Mojave-style tabs do not handle window changing focus properly

[ychin]

I'm just trying out the demo, but Mojave tabs don't seem to update their colors properly when the window gains/loses focus. You have to manually move the cursor over the tabs to update their colors. The other styles seem to handle it properly.

[barijaona]

I see similar problems with Yosemite style. If you hover over the tabs while the window is in background, then switch the window to foreground, the colors do not update correctly.

[barijaona]

When the window gains/loses focus, MMMojaveTabStyle's drawBezelOfTabBarView:inRect: method is only called once (for the first tab only).