Some tools use the block specified in the Active Block window. This includes most of the painting and drawing tools.
Blocks in the Editor UI can be drag-dropped on different locations to various effects:
- Into other UI elements (eg. tool mask) to quickly copy the block over
- Into the main viewport to fill the targeted selection (similar to Ctrl+F)
- Into the main viewport to flood replace the targeted block with the dropped block
The Active Block can be quickly set using 'pick block', which is bound to middle-click by default.