The Spraycan tool paints matching patches in a block using fabrics or colors from the Sketchbook.
You can also Drag and Drop a fabric swatch on matching colored patches of a block in the layout. Select a fabric in the palette. Click, hold and drag that fabric swatch from the palette to the quilt layout. With the arrow cursor directly over the patch you want to color, release the mouse to drop the fabric on that patch. All similarly colored patches in that block will color with the new fabric swatch. Hold the CTRL (Command) key down and drag to a patch to replace the fabric currently in that patch, anywhere it appears in that block and all other matching blocks. Hold the Alt (Option) key down and drag to a patch to replace the fabric currently in that patch, anywhere it appears in that block and alternating matching blocks.