executing the att little macro tl.C correctly displays the formula using TMathText.
However moving the mouse pointer into the canvas root crashes.
The att trace with gdb shows that code is reached (TLatex::Analyse) which should
not be executed in this case. This one can see at the very end of the trace log
where I set a breakpoint at TLatex::Analyse. This is not reached when painting
the formula but when moving the mouse pointer into the canvas.