Default settings.
New tab.
Type some (or dozens of) characters in the 1st line.
Select any character(s). <!>
Use “Select Line” command.
*1* The result is not correct, which is actually in multiple-selection mode.
Then press Del key.
Undo.
*2* It could crash. (Could crash silently, content could be lost.)
*3* If it doesn’t crash, the undone result is not correct: the character(s) selected in step <!> are missing, and the new line character is changed.
*4* “Ignore” button is not quite reliable. After ignored, the view could look unstable (e.g. Line Numbers and Ruler are missing).
*5* Both “Ignore” and “Crash” could get stuck. (Ctrl+Alt+Del has to be used.)
BTW,
In “All Commands” menu, the command name is “Select line”. (“l” is lowercased.)