Fix selection lost on keyup

[nicot]

Fixes #348.

Currently, releasing a key destroys the selection, even a modifier key like shift or command. This leads to bugs like microsoft/vscode#15200. This does not change the behavior that inserting a character will remove the selection.

This is the same behavior that other terminals have.

[Tyriar]

Thanks for looking into this @nicot! @parisk do you know why this was added originally? Perhaps about redirecting the focus from the element to the textarea or something?

[parisk]

@Tyriar yes, mostly because of that.

[parisk]

Thanks for your contribution @nicot! One thing that does not work in this PR, but used to work and works on my local terminal as well is:

1. Select some text
2. Copy
3. Press Ctrl + V (or Cmd + V on your Mac)

I expected it to paste, but it didn't. Can you please take care of that before moving on?

[nicot]

@parisk: Whoah, that is definitely not good, I'm glad you caught that! Weirdly enough, I can't get that to happen on my computer running macOS in Safari, Firefox or Chrome.

What browser/OS are you running?

[parisk]

NP @nicot! I am on macOS Sierra Chrome.

[nicot]

I run the same system, and I can't reproduce the issue you're running into. Pasting is working fine for me.

I think pasting happens on keydown, not on keyup, so this shouldn't change anything there.

[parisk]

Could you please try in another browser as well or try disabling your add-ons?

I am still running into this issue and after running the following code in the console the issue goes away (along with the functionality of this PR 😅 ):

term.element.addEventListener('keyup', term.focus.bind(term));

Update: I am always testing upon the plain demo.

[nicot]

I can't reproduce this at all! I've tried three different browsers, in Incognito mode and with extensions disabled. I'll close this PR, as I can't debug this issue further without reproducing it.