When you open multiple PDFs, they're shown as tabs in the same Acrobat window. If you would then switch to tiled view (Shift+Ctrl+l) they become split into separate windows. That's odd.

Bug: Ctrl+Shift+l is supposed to place them side by side, in a row, but they're tiled on the screen, so that 4 PDFs are distributed in 2x2.

Feature request: do not split the tiled view into separate windows. Do the same as in Indesign. 2 up vertical etc., all in one window. Why? If you want to have them back into one window again there is no action for that. You would have to pick a window and drag the other windows's tabs into it. That's pretty annoying.