Continuing the discussion from Hub Update 2.0.3:
In case anyone else was having trouble figuring out how to do this:
While viewing your Hubitat Hub's Apps or Devices in list view, click the grey "X" next to the list/grid view buttons, here:
A new "Disable" column will be revealed where you can select / de-select which Apps or Devices to disable:
If any Apps or Devices are disabled, no indication is given while in Grid View. However, while in List View, even if the red "X" is pressed to hide the Disable column, on subsequent views of the hub's Apps or Devices page, the Disable column will be visible again.
Viewing the an App's Info (Status) or Configuration page will display "App is Disabled" in red, and similarly, viewing the device details page of a disabled device will display "Device is Disabled" in red.
For Apps that produce "child" apps, such as Rule Machine and Groups and Scenes, those child apps can be disabled / enabled on an individual basis.
It would be a good idea to exercise extreme caution when using this feature to disable Apps, and especially individual Rule Machine rules, as they can be interdependent and disabling one could wreak all kinds of "havoc" and unexpected consequences on your automations.
On a personal note, I just want to say that the addition of this feature is extremely welcome, especially in terms of troubleshooting, and again helps to elevate Hubitat to a whole new level of local home automation and control.