I'm Using the TMSFMXpageControl to move between pages, it has one stroke that I can not take off and I can't find where it is set. This dotted stroke is not set by any property and it appears that I can not take it off!

You can turn off the focus border for a tab under TMSFMXPageControl1.TabAppearance.ShowFocus := False;

Thanks! I still have complications with the Page control though.
i.e. I can't get stroke under the tab. (See attached).
Also the fill.color property doesn't seem to have any effect on the tab (plain 'fill' not 'activeFill' etc. ) except when setting to null, otherwise, it stays one color and does not change when changing color.

The stroke is automatically overriden to flow inside the active page. This is by design, so you cannot add a stroke there. For the Fill, did you also set Fill.Kind?