TQTaggable list overwriting

If a tag is defined as a list, eg. key={a,b,c,d}, and then overwritten by a shorter list, eg. key={a0,a1,a2}, the current behaviour results in

key.0=a0
key.1=a1
key.2=a2
key.3=d

I suggest to add the following lines here:

if (this->getGlobalOverwrite(true))
  removeTagV(key);

The method removeTagV(...) still has to be written.