We believe that this is actually a bug in Citrix Workspace App, not Toad. You don't have to be actively using Citrix Workspace App. It only needs to be installed to cause problems for Toad. This began after the July 2020 update to Citrix Workspace App.
The App Protection option of Citrix Workspace app seems to have a keyboard hook and is incorrectly processing the HC_NOREMOVE code.
Toad is not the only application to experience problems when Citrix Workspace App is installed with the App Protection Option. For example, in Excel, if I am editing a cell, CTRL+A does nothing. It should select the entire cell contents (and does when Citrix is not installed). Toad's problem is more severe, but this illustrates that Citrix Workspace App is causing problems for other apps.
I have opened a support case with Citrix. I'll update here what they say.
Solution for Toad 14.0 or newer
- Edit Toad.ini (click here if you need help finding it).
Solution for Toad 13.3 and older
- If you don't need Citrix Workspace App, uninstall it.
- If you need Citrix Workspace App, uninstall it and reinstall with the "App Protection" option unchecked.
Update 2/10/2021: There is a new version of Citrix Workspace App, version 2102, that resolves the problem. You can get it here: Citrix Workspace app 2102 for Windows - Citrix