Created attachment 152688 [details] file containing 2 frames Open FramXY.odt, click 2nd frame (y), format it: Frame&Object>Properties>Options>Name: FrameX, enter. Reopen Options: the old name (Frame2) is back. LO refused the name FrameX because it already exists —good; but it should have issued a warning.
Better yet: LO should refuse the existing name and keep the window open for correction.
I confirm it with Version: 6.4.0.0.alpha0+ (x64) Build ID: ae823e4633a76d13cebc6432b9e44b9b2862326b CPU threads: 4; OS: Windows 10.0; UI render: GL; VCL: win; TinderBox: Win-x86_64@42, Branch:master, Time: 2019-06-26_23:06:07 Locale: de-DE (de_DE); UI-Language: en-US Calc: threaded If you try to change the name in the navigator, OK button is unusable. This would be a good solution. I hope you agree. I changed bug summary.