Alt + R resets to "auto" (At least for Mac, should be anything with R for Win)
Scroll the Chart with Arrow keys (press alt to scroll fast, No action for up/down)
Alt + H for horizontal line (guess what the vertical line is)
Thats it. In my opinion they could discard the option to type in the symbol and set millions of nice shortcuts instead. They kept it as they adopted the chart engine from tradingview.com i think. There it's pretty useful.
Wow, even those can save a lot of time! I used to work with the Price Range tool, but all those mouse clicks... Now, I can do it as follows:
Alt-H for a horizontal line
Shift-Drag to define a percentage
Alt-H again
Thanks much for your reply!