Block marker lines not drawn [was #7489]
{color:red}
reported by [~wissenbach] at 2008-01-11
previously known as [trac#13|http://www.textgrid.de/trac/ticket/13] {color}
Horizontal block marker lines are sometimes not drawn, especially when moving the cursor through them.
This makes the box look as if it is "open" to one side.
Possibly related: TG-36