I have the same issue, over 6 of icons for my Favorites don't hit on my Laptop screen when maximized. Laptop runs Win 10.
Attached are copies from before the last update and after the update.
Firefox 103 now applies the Windows "Make text bigger" setting as a zoom multiplier (Release Notes). You can either modify your Windows setting (if you don't need it in other applications) or add a new Firefox preference.
Windows Setting. On Windows 10, this is in the Display control panel. You can find it by typing make text bigger in the system search box:
Firefox Preference. Firefox 103 has 3 interrelated hidden settings that control the overall zoom level and whether it considers information from the system. This one seems to be working for many people to revert the latest change:
(A) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.
More info on about:config: Configuration Editor for Firefox. Please keep in mind that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.
(B) In the search box in the page, type or paste ui.textScaleFactor and pause while the list is filtered
Normally, Firefox will display a bar with Boolean Number String and a plus button. If Firefox displays a row that already has a number value, skip to step 5.
(3) Click the circular button in front of Number and then click the + button to create a new preference.
(4) Firefox should display an editing field, and show a value of 0 -- edit the value to 100 then press Enter or click the blue check mark button to save the change.
(5) If the current value of ui.textScaleFactor is NOT 100, then double-click the preference to display an editing field, and change the value to 100 then press Enter or click the blue check mark button to save the change.
Let us know whether that works for you -- fully, partially, or not at all.
