Long time lurker, first time poster just to answer this...because I had the same need earlier this week.
I mod'd the latest Metro UDF to include the tab code posted earlier in the thread.... It's dirty because I'm not as swift as some of the other folks here, but it works marginally well and themes correctly. I haven't torture tested it but I'll attach a moded Metro example UDF, it doesn't work so hot with the "Themes Demo", maybe someone else can sort that out.
I did have to include the old "GUICtrlOnHover.au3" to make the mash-up work, someone else can probably do better. It's attached below, feel free to use but BBs19 will probably spit on my butchery
MetroGUI_UDF_Tab.au3
GUICtrlOnHover.au3
Example.au3
