Graph widget config form area is too narrow if the Widget Add dialog height is just above 500 px - only a couple of fields are visible, which is inconvenient for the end user. Interesting that such behavior is only observed in 6.0 release version.

Steps to reproduce:

1. Open any dashboard in Edit mode
2. Press "Add widget" button
3. In the opened Widget config popup select Type = Graph
4. Re-size the browser so that the height of the overlay dialog would be just above 500 px.
5. Scroll down the Graph widget configuration form.

Result: Only a couple of fields are visible, it is very inconvenient to use such a form.
Expected: The height threshold from which the graph preview becomes fixed in widget config form should be increased.

Example: