The 6.18 update (25 April 2026) fixed the issue of the "YouTube: Hide Watched Videos" script where its buttons on the YouTube Search Bar did not appear correctly, as well as solving other issues. It now works very well; thanks for the prompt fix!
However, there is one minor issue that has arisen because of the 6.18 update. Namely, the ToolTip popup no longer appears when the mouse pointer is hovered over one of the "YouTube: Hide Watched Videos" buttons on the YouTube Search Bar like it did in 6.16 and earlier versions. (I am using Firefox 128.0 in a Debian-based Linux Operating System.)
I found that removing the two question marks from Line 599 of version 6.18 that wraps "?.classList?" allows the ToolTip to be displayed. (The ToolTip for hovering over a "Watched Video" icon on a YouTube Home page reads: Toggle Watched Videos: currently "hidden" for selection "misc".)
The problem line is Line 599 of version 6.18. Removing the two question marks that wrap "?.classList?" will restore the ToolTip popup. In other words, edit Line 599 from: mutations[0].addedNodes[0]?.classList?.contains('YT-HWV-BUTTONS') to: mutations[0].addedNodes[0].classList.contains('YT-HWV-BUTTONS')
The addition of those two question marks was part of the 6.16 to 6.17 upgrade, so removing them is probably not the correct solution.
The 6.18 update (25 April 2026) fixed the issue of the "YouTube: Hide Watched Videos" script where its buttons on the YouTube Search Bar did not appear correctly, as well as solving other issues. It now works very well; thanks for the prompt fix!
However, there is one minor issue that has arisen because of the 6.18 update. Namely, the ToolTip popup no longer appears when the mouse pointer is hovered over one of the "YouTube: Hide Watched Videos" buttons on the YouTube Search Bar like it did in 6.16 and earlier versions. (I am using Firefox 128.0 in a Debian-based Linux Operating System.)
I found that removing the two question marks from Line 599 of version 6.18 that wraps "?.classList?" allows the ToolTip to be displayed. (The ToolTip for hovering over a "Watched Video" icon on a YouTube Home page reads: Toggle Watched Videos: currently "hidden" for selection "misc".)
The problem line is Line 599 of version 6.18. Removing the two question marks that wrap "?.classList?" will restore the ToolTip popup. In other words, edit Line 599 from: mutations[0].addedNodes[0]?.classList?.contains('YT-HWV-BUTTONS')
to: mutations[0].addedNodes[0].classList.contains('YT-HWV-BUTTONS')
The addition of those two question marks was part of the 6.16 to 6.17 upgrade, so removing them is probably not the correct solution.