🐞Youtube layout changes when browser is fullscreen

Concise Description

I had found a very specific combination of settings that allowed me to configure YouTube to look like this:

But since around a month, the layout simply changed to something more broken:

No changes have been made in the settings, but I noticed that if I don't have the browser in full screen, the first layout appears:

(Ignore the mixes breaking the videos, as that's a different issue in itself)

I'm unable to decide which of the two views is supposed to be the correct one, as the result I got before didn't really match with the settings I had.

In my testing, I have found that this issue happens when the width above 1951~1952px, regardless of the height:

As stated next, this issue is happening to me in OperaGX. I haven't tried in other browsers.

Thank you so much, and good luck!

Browser/s

Opera GX

Other Browser:

No response

'Steps to reproduce' - Which of our features is required for the bug to happen?

Open YouTube (any video)

Since when?

Unable to tell who updated, it was a month ago at most.

Does the bug still happen when you log out of YouTube?

Yes

..No? Then please paste your yt.config_.EXPERIMENT_FLAGS. Twice (With the error & Without)

No response

Are any errors or related log-messages shown in the Browser-Console? (F12)

No response

Tested as the only active extension? (incognito mode or another browser users):

Yes

Expected preferred behavior:

No response

ImprovedTube Version

4.1122

Your Settings (From the Extension's ⋮-Hamburger menu > Settings > Backup & reset > Export settings)

{"add_scroll_to_top":true,"always_show_progress_bar":true,"below_player_pip":true,"below_player_screenshot":true,"channel_hide_featured_content":true,"channel_trailer_autoplay":false,"channel_videos_count":false,"chapters":false,"columns":true,"comments":"collapsed","comments_sidebar":true,"comments_sidebar_scrollbars":false,"comments_sidebar_simple":false,"compactSpacing":false,"cursorLighting":false,"day_of_week":false,"description":"normal","disable_thumbnail_playback":true,"font":"Roboto+Mono","forced_theater_mode":true,"header_hide_country_code":true,"header_hide_logo":false,"header_hide_right_buttons":false,"header_improve_logo":false,"header_position":"hover_on_video_page","header_transparent":false,"header_transparent_alternative":false,"hide_animated_thumbnails":true,"hide_author_avatars":false,"hide_clip_button":"hidden","hide_comments_count":true,"hide_date":false,"hide_details":false,"hide_gradient_bottom":false,"hide_more_button":true,"hide_playlist":false,"hide_report_button":false,"hide_save_button":"hidden","hide_shorts_remixing":true,"hide_sidebar":false,"hide_thanks_button":"hidden","hide_thumbnail_overlay":true,"hide_views_count":false,"hide_voice_search_button":true,"how_long_ago_the_video_was_uploaded":false,"join":"hidden","lastDarkTheme":"dark","lastLightTheme":"custom","likes":"icons_only","livechat":"hidden","mark_watched_videos":true,"no_page_margin":false,"player_color":"green","player_hamburger_button":true,"player_hide_skip_overlay":false,"player_rotate_button":true,"player_show_cards_on_mouse_hover":false,"player_size":"full_window","player_transparent_background":false,"popup_ad":false,"popup_window_buttons":false,"purchase":"hidden","red_dislike_button":false,"relatedVideosPrev":"notTitles","related_videos":"hidetabs","remove_black_bars":false,"remove_history_shorts":true,"remove_home_page_shorts":true,"remove_related_search_results":false,"remove_shorts_reel_search_results":true,"remove_subscriptions_shorts":true,"remove_trending_shorts":true,"scroll_bar":"hidden","sidebar_left":true,"squared_user_images":true,"subscribe":"hidden","theme":"custom","theme_primary_color":[0,0,0],"theme_text_color":[190,73,73],"thumbnails_hide":false,"thumbnails_quality":"default","thumbnails_right":false,"track_watched_videos":true,"transcript":false,"undo_the_new_sidebar":true,"watched":{},"youtubeDetailButtons":"normal"}

Your YouTube-Document

No response

OS / Device:

Windows 10

Reproduce the issue by opening any YouTube video in Opera GX with the exported settings, comparing fullscreen and non-fullscreen browser windows around 1951–1952px width. Trace the extension behavior responsible for the layout change and verify the intended layout remains consistent above that width; the issue provides no file or test entry point.