OS Windows 10 Pro (x64) Fall Creators Update 1709 (Build 16299.64)
After Opera Developer update from version 51.0.2776.0 (x64) to 51.0.2791.0 (x64) the text on the corner left Opera Menu button and all text on my Bookmarks Bar became much smaller (tabs text remains larger and unaffected. The size of the text in the bar is NOW the same as that seen in bookmark drop-down lists (which remains as before)
I uninstalled reinstalled - same result. I did a clean install without retaining my user data - same result. I installed 51.0.2776.0 (x64) and the Font sizes went back to normal (larger) but as soon as Opera did its automatic update to 51.0.2791.0 (x64) they became small again.
With the fonts at the new reduced size they are uncomfortably small on my 1920 x 1080 monitor.
Has this happened to other? Any ideas how to resolve please?
I can confirm the latest Stable and Beta Opera releases do not have this issue and neither do all Developer releases up to and including 51.0.2776.0 (x64). Hope this info helps