I don’t know if a similar solution has been posted, but I have found a way to create boxes with pedal lines. I enclose a video showing the method. It is very important to copy and paste the pedal line in INSERT mode. It took me a while to discover that pedal lines can be copied at the same place if you have the insert mode on, otherwise you can’t!
- Create a pedal line
- Hide the word and select the hook as line beginning.
- Choose the thikness of the line that you want.
- Position the extremes of the line as desired.
- Copy and paste the line in INSERT mode.
- Position the copied line over the staff and lengthen the hooks downwards.
- Select both pedal lines and choose “suppress playback”.
I hope this is helpful to somebody!