Bug while changing between an Active to non-active object in Migrate-Datasets pane

Hello,

1) Active object under Migrate-->Datasets pane selected.

At source pane we are able to add a new source.

2) Changing from the active to the non-active object.

The Add source button (+) is still there, but the object is marked as Inactive.

3) You could press the Add source button, but an error is shown without any relevant message. Unknown error. At least, we could set nothing in the Add source pop-up window, it is blocked.

4) Workaround: You have to refresh the entire site (F5 button in browser) to see how the Add source button is gone.

It seems that the Source panes refreshes, but not the Source pane buttons.

Please, find enclosed screenshoots of every single step.