When you drag multiple values for a dimension to the panel segment area and hold down SHIFT you can turn it into a dropdown to select each of the individual values. However it would be very useful to be able to just drag the dimension itself and get a dropdown of all valid values for that dimension
Why is this feature important to you
It would massively simplify the creation of dashboards for things like campaigns where you can create a single campaign performance dashboard, but then have a dropdown of all available campaigns so you can select the one you're interested in (or choose ALL) to see performance for all campaigns.
How would you like the feature to work
In a similar way to holding down SHIFT when dragging multiple values, maybe if I drag a single dimension and hold down CTRL-SHIFT it creates a dropdown of values for that dimension instead
Currently if you drag a single dimension it just adds a "dimension exists" segment.