Change:
left: unset !important; } <del> .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab.sizing-shrink.tab-actions-left::after, .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab.sizing-shrink.close-action-off::after, .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab.sizing-fixed.tab-actions-left::after, .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab.sizing-fixed.close-action-off::after { content: ''; </del> <ins> .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab .tab-fade-hider { display: none; } .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab.sizing-shrink.tab-actions-left .tab-fade-hider, .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab.sizing-shrink.close-action-off .tab-fade-hider, .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab.sizing-fixed.tab-actions-left .tab-fade-hider, .monaco-workbench .part.editor > .content .editor-group-container > .title .tabs-container > .tab.sizing-fixed.close-action-off .tab-fade-hider { </ins> display: flex; flex: 0; width: 5px; /* reserve space to hide tab fade when close button is left or off (fixes https://github.com/microsoft/vscode/issues/45728) */

Discussion:
<!-- Do Not Delete This! featurerequesttemplate --<!-- Please read our Rules of Conduct: --<!-- Please search existing issues to avoid creating duplicates. --<!-- Describe the feature you'd like. --As introduced in version 1.87.0 () drag&drop tabs now features a border indicator. It would be nice to have an option to disable this indicator. (Indicator also makes tabs width change and subsequent unwanted jump effect but that's perhaps a bug issue.) !
If you are not interested in seeing the indicator you can change it's colour to be transparent the following way: Regarding the jumping of the tabs, this is definitely a bug, however, I am not able to reproduce it so it seems like it might be related to some none default setting. Could you share the none default tab related settings you are using?
Of course, I believe jumping of the tabs is related to:
I've tried this but I do not see any jumping ! Possibly related to zooming, what are you using?
I've debugged my a bit and it seems combination of these settings is the culprit:
I have tried the combination of these two settings and it doesn't lead to any jumping in my case.
That's odd. I've tried my installation only with these two settings active (1.87.1 on latest macOS) and I can reproduce the bug. !
I tested it on windows, will try it out on a mac next week.
This issue has been closed automatically because it needs more information and has not had recent activity. See also our guidelines. Happy Coding!
I tried the drag and drop on a macos and was also not able to reproduce your bug. Will leave the issue closes for the moment.
Are you sure you've tried the settings above? I was able to reproduce the bug on different MacBook as well as on Windows machine.
I'm able to reproduce now. Looking into it.
In this specific scenario (actions left and shrink tab) we set an ::after element of width 5 for the shadow effect, however, we also use the ::before and ::after elements for drag and drop. Will try to fix next week. Could be a bit tricky