On macOS 15 beta 7 and macos 15.1 beta 2, OneThing has ui issues.
This issue is continuation from recent issue, but after discovering the cause of the issue I was having, I thought it would be more suitable to make new issue with appropriate title.

I've tested OneThing on macOS 14(VM) macOS 15 beta7(VM) and macOS15.1 beta 2(Native).
While OneThing worked without issue on macOS 14, It had issues on macOS 15 and 15.1.

[macOS 14 on virtual machine] works without UI issue, "..." is visible and it works.

[macOS 15 beta 7 on virtual machine] "..." is not visible and can't access OneThing's setting window.

[macOS 15.1 beta 2 on my device] "..." is not visible, but also, "Press the return key..." text that should be on the bottom of the edit window is not visible too, can't access OneThing's setting window.

Although these issues are from macOS beta builds and could be fixed by Apple when they release public versions of macOS 15, I think these might be notable issues that needs fix from app developer, since macOS 15 beta will soon enter release candidate phase and won't get much bug fixes.