Fixed bug 3449 by Stefan Schimanski:

Fixed bug 3449 by Stefan Schimanski:
http://bugzilla.lyx.org/show_bug.cgi?id=3449

One problem was no metric calculation was done for insets on cursor movement. Of course scrolling or entering character caused the missing metric calls, hence the described behavior in the bug report. This is fixed by re-implementing idxLast(), idxFirst() and notifyCursorLeaves().

Another problem was that 'a' and '1' were drawn at the same position because of a mis-calculation of the x-position in InsetMathMacro::draw().

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@17826 a592a061-630c-0410-9148-cb99ea01b6c8