When running a .exe-job containing a custom dialog action, the icons (tooltip-icons, icons needed by the date-selection util etc.) inside the custom dialog are not displayed at all like in the image displayed on the left.
This problem occurs only in the context of .exe-jobs. It does not affect jobs running from within the console, diagent or the job designer. The underlying culprit has to do with the fact that the custom dialog relies on Internet Explorer to render its entire UI (which is essentially an HTML front-end). Any and all resources needed by IE (images, glyph-icons etc)
Workarounds / Resolution
Before running the affected jobs you need to make sure that you have copied over the .dll called WinAutomation.Shared.Runtime.JsNativeResources.dll (no renaming allowed) inside the same directory that the .exe-job resides in. After that you may run the job and the issue should be gone.