I'm not sure exactly how to describe this but here goes:
I am having this issue a lot today, where various items (divs, buttons etc) are not sitting in the right position.
They were, but are no longer.
An example (this has happened on lots of different things for me), you have two identical divs - one red, one blue.
They sit side by side, with a top margin of 100px. They inherit this from the fact they both started as say "Div_Square" then got their individual classes of "red" and "blue" to change their colour.
the red box however sits just lower than the blue... yet they both have the EXACT same positions set by that top margin.
So now I click the little arrow to increase the red boxes top margin and BOOM - it shifts position to near what it should be - you then tap the arrow to set the margin as 100px again and all is back as it should be.
It's almost as if sometimes elements forget inherited classes or something? They get confused...