> Error in startup script: can't use empty string as operand of "+" > while executing > "expr {($sw - ($w + $el + $er))/2 - [winfo vrootx $path] - $sx}"
This happened only with old window managers, not supporting the freedesktop.orgextensions. That's not the problem, but I couldn't detect this problem in my test.Thanks fore reporting! Fixed in rev. #821.