Comment 5 for bug 164526

What's happening here is that the code to paint the caret is just trying to draw
the caret in the widget which contains the frame the caret's in. But that
doesn't work because that widget is covered by the widget for the DIV. The view
manager paints everything correctly (i.e., the text that gets entered) because
it coordinates painting across widgets and knows to draw the input text box
frame inside the DIV's widget.

Fixing this could be tough. Only the view manager knows how z-order and clipping
work. To fix this we should probably move caret painting into the view manager.
Or maybe we can paint the caret using the normal paint path?