It would be helpful to have a shortcut key that will temporarily constrain the brush strokes to be perfectly straight when using the Brush Tool.
Even though we have the Straight Line Strokes option in Painter property bar you have to click on this option and then click it back to Freehand mode when finished. Implementing Shortcut key to temporarily allow you to switch between straight line and freehand, would be very helpful.
V on the keyboard is a shotcut for Straight lines. B key will take you back to the brush