Hi Elba, Thank you for your time and effort in researching this. Unfortunately, the above method you describe is more than a little awkward. When one shows the Downloaded window, as you illustrate, that greys out all the individual categories. So, if I were looking for brushes, I'd have to check if I already had it by going to the downloaded window, then navigate back to brushes by first going to Featured or Recent, and then to Brushes, (even All Categories is not clickable, though it looks active). I'd also need to have a very, very good memory, or be going back and forth very often, with how close some brushes appear, and how similar their names are.
Instead, in a browser window, I go to my library from my adobe.com page, so I can see what brushes I have while the window where I can download brushes is open:
However, this still seems awkward to me. Adobe could grey out the icons to indicate they had already been downloaded, while still allowing them to be clickable and downloadable. I guess more code would be needed. I see examples of this every day in both Apple's app store, and Google's play store. For that matter, even the Adobe CC desktop app itself informs me of what Desktop Apps I have installed on each computer, and even whether they need to be updated, though that is a bit different.