Holding alt when clicking somewhere in the text field should add another cursor at that location so that when you type, text appears at all cursors at once.
You should also be able to Hold alt when selecting/hightlighting text, so say if you already have some text highlighted and hold down alt and drag over some text that isnt highlighted yet - it will get added to the current selection rather than replace the current selection/highlight.
And finally, MMB drag could act as a box selection
This is how multi cursor editing works in VS Code ;)
Suggested controls
Holding alt when clicking somewhere in the text field should add another cursor at that location so that when you type, text appears at all cursors at once.
You should also be able to Hold alt when selecting/hightlighting text, so say if you already have some text highlighted and hold down alt and drag over some text that isnt highlighted yet - it will get added to the current selection rather than replace the current selection/highlight.
And finally, MMB drag could act as a box selection
This is how multi cursor editing works in VS Code ;)