Arrow keys in Multiline Editing Mode
I’ve enabled the Settings > Preferences > Editing > Enable Ctrl + Mouse Click/Selection feature, but I noticed that whenever I use the right/left arrow keys to move the cursor, the Multi-Edit mode is turned off and it goes back to a single line editing mode. Is there any way to use the arrow keys to move the cursor left or right while in Multi-Edit?
Its not possible currently. Internally Notepad++ uses Scintilla v3.5.6. However in Scintilla v3.6.0 it added this type of functionality. Quote from Scintilla v3.6.0 release notes:
Multiple selection now works over more key commands. The new multiple-selection handling commands include horizontal movement and selection commands, line up and down movement and selection commands, word and line deletion commands, and line end insertion.
So whenever Scintilla is upgraded internally this will be possible.