Tables (tree and list views) consist of two tables: table headings and table data. Since there are no TH (table header) elements a screen reader cannot read the header value before the cell value. This is a problem because tables are different from one app to the next, they have different columns and the columns are customizable. It is impossible to learn which column a value represents when you hear the screen reader speak it.

The new Vaadin tree grid is a single table with all the expected elements (thead, tbody, th, td). Retest what the screen reader speaks when the new tree grid is implemented. Some new accessibility labels may be needed for header cells. The new tree grid is also aware of which cell has focus.