There is currently no shortcut to enable or disable the "Mouse Pointer as Pen" feature during a presentation. The only way is via the right click context menu, or by enabling it beforehand in the Slide Show Settings.
There is a workaround by creating a macro and assigning that macro a keyboard shortcut (https://forum.openoffice.org/en/forum/viewtopic.php?f=20&t=60626), but this is complicated. The "Mouse Pointer as Pen" option should be directly bindable to a keyboard shortcut.
PowerPoint has this feature bound to Ctrl+P to enable, and Ctrl+A to disable, both of which currently do nothing during a slideshow in LibreOffice.
This feature has been requested before (https://ask.libreoffice.org/en/question/8200/keyboard-shortcuts-for-pen-tool-during-presentation/), but no enhancement bug was filed back then.
Tags: SLIDESHOW, UI
Steps to Reproduce:
1. Open Tools/Customize.../Keyboard
2. There is no option to assign a shortcut to "Mouse Pointer as Pen"
1. Start a Slideshow
2. Right click
3. Mouse Pointer as Pen can be enabled from the context menu, but there is no keyboard shortcut assigned to it
The only way to enable the pen tool is via the context menu.
There should be a way to enable/disable the pen tool with a keyboard shortcut.
User Profile Reset: No
Version: 184.108.40.206 (x64)
Build ID: c838ef25c16710f8838b1faec480ebba495259d0
CPU threads: 4; OS: Windows 6.1; UI render: GL;
Locale: en-US (de_DE); Calc: group
Sounds reasonable -> NEW