On a related note, if you are reconsidering properties panels, I strongly encourage all y'all to make them Pd patches. This is how Max/MSP does it and I think it would work very well for Pd as well. Sounds like this is a good opportunity to make the switch.
I guess (?) max uses a internal variable to connect the edit patches and GUI objects. In case the properties-patch gets implemented, I would suggest that this internal-send-mechanism doesn't interfere with the already common send-receive mechanism, as it is one of Pd's neatest and 'individual' features. For example one of the inconveniences of my gui-edit patch is that the receive-symbol (and occasionally send) of the GUi must be edited, and then put back to 'normal' (in case a $0-variable is used). With this backstage temporal connection things would be even faster.
And, still assuming that this idea would get forward, it would really be necessary to implement query of GUI objects to know all the current parameters (for now only possible with the position of a cnv). Or, as it happens now, each properties patch is made from 0. To make new objects is this works (for example, I implemented the standard values), but to edit already existing ones (2 pixels wider, slight color change, etc.) is a pain.
speaking of colour, that would bring up the colour schemes question.... well, you know what I mean. (I guess sometime all these small incongruencies will be solved, it just takes a bit of time - but the later the sollution, the bigger the problem)
Joao