Just to expand on why I think it would be useful to have a hotkey that enables or disables a specific label filter:
1] There are distinctions that are useful to display in a visual way with label filters, but which are too messy to be displayed all the time. So, for instance, sometimes I want to differentiate between files created in the last three months and those created beforehand. I can define a label filter which separates them into red and blue. But I don't want to always have these colors swimming around. Rather, in general I'd like to have the files displayed normally. However, when I do want to make that distinction, I'd like to be able to quickly hit a hotkey to invoke a label filter which would label the files in the current lister as red or blue according to their creation time. Similarly, when I'm in flat mode, I'd like to be able to invoke a label filter which colors all those files that are five-or-more levels deep in the tree. However, in general, when I'm I'm not in flat mode, such a coloring would just be a distraction.
2] Even more importantly: as Leo has mentioned in another thread ([url]Slow folder listing with SolidWorks files]), label filters based on graphics metadata can be rather heavy on the system. I wouldn't want such metadata label filters to be in effect all the time, because it could cause significant lag, especially when dealing with directories with thousands of photos. On the other hand, I do want the ability to use a hotkey to deliberately activate such label filters as necessary, when relevant. For instance, if I am looking at a directory with a moderate number of pictures, and I want to get a quick visual indication regarding which pictures were taken with flash and which without, the ability to invoke a filter label via shortcut key would be very helpful.
So: is it possible to do this now? And, if not, would you consider adding it please to a future release?