Yay!
Can confirm.

I just noticed that, in my library's main view ("My Collection"), when I select any of my tags with which I have at least one hidden game tagged (in addition to non-hidden ones), it no longer shows the check box at the bottom of the results that would allow me to append any hidden titles to the end of said results.
I'm guessing the loss of this feature might just be an oversight after all the messing about behind the scenes of the website recently, but it would be nice to have it back. (Actually, it would be extra cool if, when that box was checked, the relevant hidden matches were mixed into the rest of the results according to whatever sorting mode is selected, rather than being dumped all together at the end, but I'd obviously be fine with the feature simply being restored as it was. :) )