Describe the bug
As noted in #3793 (comment), when you attempt to drag a row in the simultaneous/constrained fit page, an error is throw. This error has been around for a number of releases (at least since v6.0.0)

To Reproduce
Steps to reproduce the behavior:

1. Open a constrained fit page with at least two fit tabs populated
2. Attempt to drag on of the fit page rows within the table
3. In v6.1.0 and later, an error is thrown immediately
4. in v6.0.0 and v6.0.1, a delayed error is thrown when attempting to close the application.

Expected behavior
The error should either be suppressed, or the table should allow rows to be reordered.

Screenshots
See #3793 (comment) for a video.

SasView version (please complete the following information):

• Version: 6.0.0 and above.