Accessibility observations in Subtitle Edit v5.1.0-beta5: menu navigation, DataGrid accessibility, remaining unlabeled controls, and playback behavior

I tested Subtitle Edit v5.1.0-beta5 with NVDA and wanted to share a few observations. First, thank you for the accessibility improvements that have already been implemented. The labeling work in the Settings and Shortcuts windows is noticeable, and most of the controls I mentioned previously (such as combo boxes and check boxes) are now correctly announced by NVDA.

1. Menu navigation When testing v5.1.0-beta1, I found that pressing Alt correctly activated the menu bar, allowing me to navigate both the main menus and their menu items using the arrow keys. This worked very well with NVDA. In v5.1.0-beta5, I am no longer able to do this. Pressing Alt does not appear to activate the menu bar, and the arrow keys do not navigate between the top-level menus. Expected behavior • Pressing Alt should move keyboard focus to the menu bar. • Left and Right arrow keys should move between the main menus. • Up and Down arrow keys should navigate the menu items.
2. DataGrid accessibility The largest remaining accessibility challenge is the application's DataGrid controls. Wherever a DataGrid is present (for example, in the Shortcuts window and other parts of the application), NVDA simply announces: "Data grid" After that, I am unable to interact with or explore the control using the keyboard. I cannot navigate its contents, determine what is currently selected, or obtain any additional information from the screen reader. Ideally, the DataGrid should expose its contents through UI Automation so that screen readers can announce information about the currently focused item as keyboard navigation occurs.
3. Remaining unlabeled controls Most of the controls mentioned in my previous feedback are now correctly labeled, which is greatly appreciated. However, there are still a few controls in the main interface and in parts of the Settings and Shortcuts windows that NVDA announces only as generic Avalonia controls, for example: Avalonia.Controls... These controls do not expose a meaningful accessible name, making it difficult to determine their purpose.
4. Playback controls and keyboard shortcuts I also noticed an issue related to video playback. Pressing the expected playback shortcuts, such as Space or Ctrl + Space, does not appear to start video playback. Similarly, activating the Play button in the main interface also does not seem to start playback. I'm not sure whether this is related to accessibility, keyboard focus, or a separate application issue, but I wanted to mention it in case it is relevant. Thank you again for the continued work on accessibility.