Created attachment 169878 [details]
Navigating into a folder by normal means, going back, then double-clicking Mouse9 to re-enter the folder (click 1) and open a file inside it (click 2).

SUMMARY
When the system is set up to use double-click to open files or folders, it is seemingly possible to do so in Dolphin using non-primary mouse buttons, such as the Forward and Backward navigation buttons (Mouse9/8).
This occurs even if the first click triggers history navigation.

STEPS TO REPRODUCE
1. In System Preferences, set "Clicking files or folders *selects them*".
2. In Dolphin, hover over a file or folder
3. Press either Mouse8 (Back) or Mouse9 (Forward) twice in quick succession.
(If the first click causes navigation, ensure there is an item below the cursor afterwards.)

OBSERVED RESULT
Dolphin does not navigate forward/back on the second click.
Instead, it behaves as if the item located under the cursor was double-clicked (opens files, navigates into folders).
This happens even if the first click triggered history navigation.

EXPECTED RESULT
Dolphin *does* navigate forward or back on the second click (if applicable).
The hovered file or folder is *not* opened/navigated into.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.0.5
KDE Frameworks Version: 6.2.0
Qt Version: 6.7.1
Kernel Version: 6.9.1-arch1-1 (64-bit)
Graphics Platform: Wayland

ADDITIONAL INFORMATION
Bug 485295 appears related, as it mentions the double-click delay seemingly applying to the forward/back buttons.
https://bugs.kde.org/show_bug.cgi?id=485295