Trailing whitespace highlighting+removal in editor doesn't work as expected

[darkred]

The issues I noticed are that:

• Any trailing whitespace is highlighted only after you move the cursor(with keyboard/mouse) away from the line you typed the trailing space. (but it's removed on Save while having the cursor on the current line, as expected)
• If you modify an existing line(of an already saved file), then trailing whitespace is ignored, i.e. it's not removed on Save nor highlighted

For comparison regarding the former, Sublime Text editor's 'TrailingSpaces' package highlights trailing whitespace as you type/as you still have the curson on the current line.

Thank you

STR 1

Here is a screenshot:

STR 2

• in a fresh Chrome profile, with only latest TM beta extension
• notice in TM | 'Dashboard settings' | Config mode: Advanced that the two settings Highlight trailing whitespace and Trim trailing whitespace from modified lines are enabled by default
• open TM editor, and click the button to open New Userscript
• paste the following to the editor:

  
  // ==UserScript==
  // @name         New Userscript
  // @version      0.1
  // ==/UserScript==

// some comment text

- press Save (the script tab will close), reopen the script in the editor
- move the cursor to the latest line, and delete the word `text` leaving 1 trailing space
- press Save (Ctrl-S)
- notice that the trailing space is not removed: 
![2021-01-24_000830](https://user-images.githubusercontent.com/723651/105615325-58db0580-5dd8-11eb-8655-98aeedc8062b.jpg)
- If you move/click the cursor away, then the space gets highlighted, but it doesn't get removed on Save :
![2021-01-24_000843](https://user-images.githubusercontent.com/723651/105615328-62fd0400-5dd8-11eb-8404-441b8b8023d3.jpg)

## Specifications

- Chromium: (88.0.4324.104)
- TM: (beta 4.12.6126)
- OS: (win 10)

[darkred]

I'd like to mention that these issues still occur with latest TM 4.17.6161 (Chrome 102 on win 11).

[derjanb]

I just created a new extension that allows to edit the userscripts of Tampermonkey at vscode.dev (which is basically a VSCode online editor).

I know this does not fix Tampermonkey's internal editor, but it might help. To test it you have to install TM BETA 4.19.6176+ and Tampermonkey Editors 1.0.1.

A click at "Tampermonkey Editors"' icon will take you to vscode.dev and a "folder" with all installed Tampermonkey scripts should be automatically opened.

[darkred]

Thanks for making this new extension. I tested it and works as expected, no issues noticed.

[derjanb]

Note: cm.getDoc().getAllMarks() does not include the change when this happens. This needs further debugging...