Background erase of debug variable panel was disabled for some reason, and it not anymore compatible with EVT_PAINT based refresh. It was leaving traces behind when removing traced variable. Fixed.
<xsd:attribute name="Command" type="xsd:string" use="optional" default="make -C %(buildpath)s all BEREMIZSRC=%(src)s BEREMIZCFLAGS=%(cflags)s MD5=%(md5)s USE_BEREMIZ=1 FROM_BEREMIZ=1"/>