Hey IOhannes,
With the latest revision of pd-gui-rewrite branch, the Tcl entry box  
is broken.  I am guessing something in your recent commits broke it.   
It gets caught up on the validation.  To reproduce, try typing code  
into the Tcl entry box, I get a Tcl exception that I can't get out of:
wrong # args: should be "info message"
wrong # args: should be "info message"
     while executing
"info complete $tclentry"
     (procedure "::pdwindow::validate_tcl" line 3)
     invoked from within
""::pdwindow::validate_tcl""
     (command bound to event)
.hc
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