Using an invalid URL for a Batch Account causes Add Pool sidebar to behave oddly

[theunrepentantgeek]

Describe the bug

When an invalid URL is provided for a local shared-key Batch account, the UX misbehaves in strange ways.

Full disclosure: I discovered these issues by shooting myself in the foot, repeatedly, by putting in an stunningly incorrect Batch Account URL.

To Reproduce

Steps to reproduce the behavior:

1. On the dashboard screen, add a local Batch account using a URL containing a hostname that doesn't resolve
2. Make sure the new account is selected
3. Go to the Pools screen and try to add a pool
4. While you can't click on any of the fields in the "New Pool" sidebar, you can tab through many of them and enter values using the keyboard
5. The throbber pulsing at the top of the sidebar keeps going
6. Eventually an error box is shown at the lefthand side, but it's blank

Expectation
Failure to resolve the host name should result in an actionable error message the user can address.

Screenshots

Sidebar with throbber and values entered into fields via the keyboard

Blank error display box

Version (please complete the following information):

• OS: Windows 10 Version 1809 Build 17760.1
• Batch Explorer Version: 0.17.3-insider.49