Tk-multi-app GUI issues inside of Houdini

So just for some context iv started a custom app using the tk-multi-startapp as a base that needs to span across multiple DCC’s.

Now inside of houdini any combobox or spin widgets arrows are not visible, and I cant seem to get to the bottom of what could be causing this.

I’v tried manually overriding them in the style sheet but it doesn’t seem to make a difference.

The same app shows up correctly inside of maya.

Any suggestions or possibly where to check would be appreciated.