Range Board

Marks the cuboid region that Filler mode works on. While you hold it, a mode bar is shown at the bottom of the screen.

Normal mode

Input	Effect
Right click a block	Set Pos1, then Pos2
Shift + right click	Clear the whole region

With only Pos1 set, Pos2 follows where you look and the cyan outline moves with it.

Edit mode

For fixing just one corner of a region you already marked.

Input	Effect
Alt + scroll	Switch between Normal and Edit
Shift + scroll	Pick the point to edit: none, Pos1, Pos2
Shift + left click	Clear only the selected point

The selected point follows where you look.

The mode bar

While Alt is held, a panel slides up under the bar with a description of the current mode. The bar is also hidden while the HUD is hidden with F1.