ux: loading and disabled states

Only the button that was clicked to trigger an action should be in _loading mode_. If other inputs must be blocked while the action is loading, then these should be in _disabled mode_ (as opposed to loading).
This way the user knows what button was pressed while they are waiting.

Start by locating the action buttons and input controls that expose loading or disabled states in the React app, then trace how the clicked control is identified. Done means only the triggering button shows loading, while any other blocked inputs show disabled instead; verify the relevant action flows manually.

Written by the indexing model from the issue text.