The Group Size/Drag feature allows you to handle a group of tiled windows in natural efficient manner. Tiled (or adjacent) windows are those that placed side by side without gaps or overlaps. As there are no gaps/overlaps, tiling is the most efficient way of utilizing the available screen space. Actual Window Manager provides numerous tools to arrange windows as tiles, like Snap, Aero Snap, or Desktop Divider.
Once you placed required windows to each other, you may want to adjust their sizes in according to current circumstances. Usually, you would have to resize each window, carefully trying to preserve the already arranged layout. Group Size lets you do this quicker: just start to resize a window - and all its neighboring windows will begin to change their sizes accordingly, as if they were cells in a spreadsheet.
In some cases, you may want to move the arranged layout of tiled windows to another place on the desktop (e.g. to another monitor in a multi-monitor environment). With Group Drag, you can start to drag any window in the group - and all other windows in the group will move along, as if the group were a single window.
After the feature activates, you can release the modifier keys - it will continue to work until you stop dragging.
Both features utilize the same combination of modifier keys but you can set the mode of activation separately.
Both features work when using either mouse or keyboard to resize/move a window.
While moving/sizing windows, you can press <Esc> to cancel the current operation - and all windows in the group will restore their positions/sizes.
You can combine Group Size Drag with Easy Window Dragging/Sizing by specifying the same combination of modifier keys.