
fixes https://github.com/flutter/flutter/issues/152055 Disabling filtering in `DropdownMenu` at start and after a selection has been made, and re-enable it (if `widget.enableFilter` is true) after text input. This way it doesn't hide all other options when there is an existing selection. Note: currently this may crush due to issue https://github.com/flutter/flutter/issues/151878 . Which is not directly related to this PR