When editing a large formula such as the one is https://en.wikipedia.org/wiki/Matrix_(mathematics) definition section the edit window moves about at lot.
This happens because while editing the you will create syntax errors when adding a new command, say adding the variable \theta you first have to type \the which causes an error. This in turn changes the displayed equation to a long error message which has a different size to the equation, both the height and width change. The editing window seems to be positioned center aligned with the bottom displayed equation. So its position moves.
This behaviour is really distracting as the place your editing keeps moving. There might be a way to position the edit window with a more stable position, making it left aligned would reduce some of the problem.
Still better would be some other way of indicating errors.Say display the last working formula together with turning the done button red and making it inactive. This would have the beneficial side-effect of preventing broken code being inserted.