EDIT

Quantitative data can be entered into the matrix very fast by only using the keyboard via return, left, right and number keys.

For categorical data this works not the same way. If entering text the dropdown opens but the text is written no-where. Better one should jump into the filter field and immediately write there (1). When in the filter field one should have the possibility to go to the records by using the arrow keys (2).

Also when a field is selected by pressing the left or right tab key the selected value should be written into the field and the next cell should be selected. This sometimes works but often no value is written into the field. (same seems to happen with "return" but less often).

Writing into the filter field only works when one of the values selected, this is shown by the checkmark. Therefore you have to use the arrow keys. But we should find a way that the filter field reacts to the writing immedtiately.