Thanks, I agree that one is somehow warned by that feature that some windows will show up when clicking on a programs icon and that one could use this as a visual hint that there is still unfinished work (open windows) in a certain application.

But I still don't understand why knowing that an app (e.g. Safari) has open windows would make you less likely to click on it.

If I click on the Mozilla icon, I do this to open a webpage, knowing that there are already several open Mozilla windows would not stop me from doing this. If I want to open a webpage I have to click on its icon, there is no way around it (actuallly there is, I could use another browser, but I don't think that is the point).

My thinking is kind of the other way around from what Rob described: when I hide an app with many open windows, I like that the dock icon also goes translucent.

Of the windows that remain visible, it's fairly easy to glance at the dock, note the dark triangles, and know which windows are currently on the desktop and which ones are hidden.

When everything is overlapped and you can only see a sliver of some windows -- if that much -- this can be useful.

If you want to clear off some space, the same trick can apply -- the Finder is already hidden but Safari & Terminal are both unhidden. I'm not using Terminal at the moment, let's get those five windows out of the way for a little while. Etc.

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DO NOT LEAVE IT IS NOT REAL