First word disappears after pressing Space in the New Tab search field when typing in Bulgarian (Linux / Wayland)

   • Firefox 153.0.1 (64-bit)
   • Ubuntu 24.04.4 LTS
   • Wayland session
   • Input method: IBus
   • Keyboard layouts:
       ◦ US
       ◦ Bulgarian (bg+bekl)
   • Graphics:
       ◦ AMD Radeon Graphics (renoir)
       ◦ WebRender (Software)

   1. Open a new tab (about:newtab).
   2. Click inside the center search field.
   3. Switch to the Bulgarian keyboard layout.
   4. Type the first word, for example:   български
   5. Press the Space key.

   • The problem does not occur when typing in the Firefox address bar.
   • The problem does not occur on google.com or in other web page input fields.
   • The problem is reproducible in:
       ◦ Troubleshoot Mode
       ◦ a brand new Firefox profile
   • No third-party extensions are installed (only the built-in OpenH264 codec is present).
   • Setting

   • Disabling

   • If the address bar already contains text before clicking into the New Tab search field, the issue may no longer reproduce. This suggests that the bug could be related to focus handling or interaction between the New Tab search widget and the address bar.

Environment • Firefox 153.0.1 (64-bit) • Ubuntu 24.04.4 LTS • Wayland session • Input method: IBus • Keyboard layouts: ◦ US ◦ Bulgarian (bg+bekl) • Graphics: ◦ AMD Radeon Graphics (renoir) ◦ WebRender (Software) Summary When typing a multi-word search query in Bulgarian into the center search field on the Firefox New Tab page (about:newtab), the first word disappears immediately after pressing the Space key. The issue occurs only in the in-page search field. Typing exactly the same text in the Firefox address bar works correctly. Steps to reproduce 1. Open a new tab (about:newtab). 2. Click inside the center search field. 3. Switch to the Bulgarian keyboard layout. 4. Type the first word, for example: български 5. Press the Space key. Actual result The first word disappears completely. The search field becomes empty and the caret remains after one blank space. Typing continues normally from the second word onward. Interestingly, pressing Ctrl+Z immediately restores the missing first word, indicating that Firefox performs an undoable edit operation rather than simply ignoring the input. Expected result The first word should remain in the search field after pressing Space. Additional observations • The problem does not occur when typing in the Firefox address bar. • The problem does not occur on google.com or in other web page input fields. • The problem is reproducible in: ◦ Troubleshoot Mode ◦ a brand new Firefox profile • No third-party extensions are installed (only the built-in OpenH264 codec is present). • Setting browser.newtabpage.activity-stream.showSearch = false removes the in-page search field, therefore the issue disappears because the affected widget is no longer present. • Disabling browser.search.suggest.enabled does not change the behaviour. • If the address bar already contains text before clicking into the New Tab search field, the issue may no longer reproduce. This suggests that the bug could be related to focus handling or interaction between the New Tab search widget and the address bar. Reproducibility Always reproducible on this system. Notes The issue appears to be specific to the Firefox New Tab search widget (about:newtab) rather than to the operating system, keyboard layout, input method, or user profile. ____________________________________________________________ The text above was created following extensive discussion and numerous tests, in collaboration with ChatGPT.