Within the method "setTarget(..)" of basefocusview, there is bug, which will cause umlimited registration to the events "onwidth" and "onheight" of the canvas.
(sourcecode is copied from base/basefocusview.lzx#setTarget(..), l. 184 to l. 197 )

As you can see in the sourcecode, after the while-loop the variable "p" will have the value "canvas"
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  var p = newtarget;
  var i = 0;
  while ( p != canvas ) {
    this._xydelegate.register(p, 'onx');
    this._xydelegate.register(p, 'ony');
    p = p.immediateparent;
    i++;
  }
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Now we create new LzDelegates...
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  if ( !this._widthdel ) this._widthdel = new LzDelegate(this, "followWidth");
  if ( !this._heightdel ) this._heightdel = new LzDelegate(this, "followHeight");
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And now we will register the delegates to the events "onwidth" and "onheight" of the canvas (as p==canvas, see above!).
This will happen everytime we pass this part of the method, so everytime we invoke setTarget(..).
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  this._widthdel.register(p,'onwidth');
  this._heightdel.register(p,'onheight');
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To stop this unwanted behaviour change the source like so (l.193 to l.197):
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  if ( !this._widthdel ) {
    this._widthdel = new LzDelegate(this, "followWidth");
    this._widthdel.register(canvas,'onwidth');
  }
  if ( !this._heightdel ) {
    this._heightdel = new LzDelegate(this, "followHeight");
    this._heightdel.register(canvas,'onheight');
  }
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