Home » Tip of The Day » See The Brush Size On The Magnetic Lasso ToolSee The Brush Size On The Magnetic Lasso Tool May 15, 2016. Posted in: Tip Of The Day. When using the Magnetic Lasso tool, press the Caps Lock key to change the cursor to the brush-size indicator. This lets you see more precisely the area that the tool is selecting from. You can use the Bracket keys ( [ or ] ) to change its size. « Previous Photoshop Tip: | Next Photoshop Tip: » Sign-up for the PTC Newsletter so that you'll never miss a tutorial!. Your Email Address: