Upon first load Icons do not load

[DannyBrown-xx]

Having loaded up MuseLib for the first time and preceding to browse to a new folder to be my muslib library the MainWindow opens for the first time.

I can see the outline of some buttons but they are unstyled.

To fix it you only have to select a theme from the menu. Subsequent loads work as intended.

OS X El Capitan.

[Godley]

Actually this is a known hack fix. I think.
I don't remember which way I fixed it tho - the original problem being fixed was that on OSX if you applied the theme straight away the menu bar wouldn't load. The get around was either waiting till the user clicked anything or pausing between opening and loading the theme.
Either way needs more work. But that's the reason it looks shit for a bit.