Tips for mouse/trackpad (desktop) use

the right mouse button can always be used to swipe.

unless in drag mode, the left mouse button can also be used to swipe.

when in drag mode, the left mouse button can used to drag selected thumbnails to another browser

the mouse pointer indicates the mode, when moved over a thumbnail

hold down the right mouse without swiping to toggle drag mode

hold down the left mouse without swiping to toggle preview playback