Delete sources dialogue (when no sources selected) - can't click OK

[deeplow]

Description

When no sources are selected and the delete sources button is clicked it does show the dialogue, but the "continue" button does nothing. This happens in the client 0.14.0 (currently in release process) (CC @zenmonkeykstop)

Steps to Reproduce

No sources are selected and the user clicks "delete sources" button.

Expected Behavior

Clicking on the CONTINUE dismisses the dialogue

Actual Behavior

The button does nothing:

Comments

Instead of letting the user click "continue", perhaps we could simply disable / grey out the "delete sources" button when no source is selected. This would follow the usability heuristic #5:

5: Error Prevention

Good error messages are important, but the best designs carefully prevent problems from occurring in the first place. Either eliminate error-prone conditions, or check for them and present users with a confirmation option before they commit to the action.

-- https://www.nngroup.com/articles/ten-usability-heuristics/

[zenmonkeykstop]

If you click the Delete Sources button on startup, before any source has been selected, nothing happens at all. It's another inconsistency but more in line with the suggested behavior above.