[BUG] "4 Spaces Tab" doesn't play well with Copilot inline suggestions

[AndersHogqvist]

Describe the bug
The "4 Spaces Tab" setting seems to take priority over other actions, basically inactivating things such as accepting Copilot inline suggestions.

I've spent some time trying to figure out why pressing tab doesn't accept inline suggestions from Copilot. I finally realized that it was the "4 Spaces Tab" setting in RobotCode that was the culprit, when I deactivated that it started working. At first I didn't understand why this setting exists at all but after a short while I realized that I don't always get 4 spaces when pressing tab.

Steps To Reproduce
Steps to reproduce the behavior:

1. Activate Copilot inline suggestions
2. Start writing code
3. Wait for a Copilot inline suggestion to appear
4. Press tab

Expected behavior
When there's one or more active inline suggestions, pressing tab should accept the suggestions.

Additional context
I've been trying to modify the key bind for this function but with no success. If I for instance add && !inlineEditIsVisible to the "When Expression" I can see in the debug log that it triggers the correct action but now it doesn't do anything (neither accepting inline suggestion nor inserting spaces):

2026-01-28 14:08:46.641 [info] [Window] [KeybindingService]: / Soft dispatching keyboard event
2026-01-28 14:08:46.641 [info] [Window] [KeybindingService]: | Resolving Tab
2026-01-28 14:08:46.642 [info] [Window] [KeybindingService]: \ From 13 keybinding entries, matched type, when: config.robotcode.editor.4SpacesTab && editorTextFocus && !editorHasSelection && !inSnippetMode && !inlineEditIsVisible && !inlineSuggestionVisible && !suggestWidgetVisible && editorLangId == 'robotframework' || config.robotcode.editor.4SpacesTab && editorTextFocus && !editorHasSelection && !inSnippetMode && !inlineEditIsVisible && !inlineSuggestionVisible && !suggestWidgetVisible && editorLangId == 'robotframework-repl', source: user.
2026-01-28 14:08:46.642 [info] [Window] [KeybindingService]: / Received  keydown event - modifiers: [], code: Tab, keyCode: 9, key: Tab
2026-01-28 14:08:46.642 [info] [Window] [KeybindingService]: | Converted keydown event - modifiers: [], code: Tab, keyCode: 2 ('Tab')
2026-01-28 14:08:46.642 [info] [Window] [KeybindingService]: | Resolving Tab
2026-01-28 14:08:46.642 [info] [Window] [KeybindingService]: \ From 13 keybinding entries, matched type, when: config.robotcode.editor.4SpacesTab && editorTextFocus && !editorHasSelection && !inSnippetMode && !inlineEditIsVisible && !inlineSuggestionVisible && !suggestWidgetVisible && editorLangId == 'robotframework' || config.robotcode.editor.4SpacesTab && editorTextFocus && !editorHasSelection && !inSnippetMode && !inlineEditIsVisible && !inlineSuggestionVisible && !suggestWidgetVisible && editorLangId == 'robotframework-repl', source: user.
2026-01-28 14:08:46.643 [info] [Window] [KeybindingService]: + Invoking command type.

Desktop (please complete the following information):
VS Code Version 1.108.2
RobotCode Version 2.2.0
OS: Windows
Python Version 3.11.9
RobotFramework Version 7.4.1
robocop 7.2.0
tidy 4.18.0

[d-biehl]

On my side this works fine, see the video... I can write senseless test cases only with enter and tab ;-) ... or do I understand something wrong or miss something?

Video.Project.mp4

[AndersHogqvist]

Turns out it's only an issue in particular scenarios. I can do what you do as long as the suggestion refers to text at the cursor position. If it's a suggestion in a different place a tab will insert 4 spaces instead of accepting:

4spaces_issue.mp4

[AndersHogqvist]

And in this scenario I also get 4 spaces instead of accepting the suggestion:

Note the difference in appearance of the suggestions, when it's working the suggestion appears as slightly faded text but when it doesn't work the suggestion appears differently. I assume it's because the source of the suggestion is different? The latter seems to be Copilot and the former seems to be the IntelliSense feature(?)

[d-biehl]

Ok, I see. I’m not sure whether the same should apply when using Tab, though. I’ve seen similar suggestions in Python code as well, and I’m wondering how to accept them. I’ll need to take a closer look, but RoboCon is coming up and I have to prepare a workshop and a talk, so it may take a bit of time.

[AndersHogqvist]

If I turn off "4 spaces tab" I can accept those suggestions with tab, same as in other languages

[AndersHogqvist]

If I add !tabShouldJumpToInlineEdit I get it to jump to the next suggestion. If I also add !tabShouldAcceptInlineEdit it accepts the suggestion when it looks like "scenario 2" in my clip above. However, with those two additions to the "when expression" for 4spaces nothing happens when I press tab when there is no inline suggestion even though I can see in the debug log that it resolves to 4spaces and triggers the type action.

config.robotcode.editor.4SpacesTab && !tabShouldJumpToInlineEdit && !tabShouldAcceptInlineEdit && editorTextFocus && !editorHasSelection && !inSnippetMode && !inlineSuggestionVisible && !suggestWidgetVisible && editorLangId == 'robotframework' || config.robotcode.editor.4SpacesTab && !tabShouldJumpToInlineEdit && !tabShouldAcceptInlineEdit && editorTextFocus && !editorHasSelection && !inSnippetMode && !inlineSuggestionVisible && !suggestWidgetVisible && editorLangId == 'robotframework-repl'