@edhans greying out non-active windows is a pretty standard UX method of highlighting what is in focus. Since that is what we have been doing up until now, it's more consistent to still do something.
You can still disable greyscale in the client to disable the effect if you prefer.
Interesting. I am not a developer, but in just looking at how macOS and Windows handle apps that are not in focus, none of the apps I use, besides LogMeIn, switch background apps to greyscale or black. They just show the apps in their normal color. This includes Chrome, Safari, Office apps (Excel, Word, etc.), Power BI Desktop, Evernote, Crystal Reports, Edge, NotePad++, all of my Mac apps (Messages, Reminders, etc.).
None of them go greyscale when not the active app.
Can you give other examples besides LogMeIn where it is standard to switch to grayscale when not active?
Seems to me it is better to do nothing and leave the apps visible and in color vs a black box.
I use logmein client to connect to a computer across the Atlantic, and had this same problem. I notice that the new logmein client update, version 4.1.6934 appears to have solved the crash problem that occured if you opened another window. What a relief!
I'm assuming this complete blanking out of the screen when inactive now (or leaving fully coloured) is a temporary fix? I suppose having it remain in colour is perfectly fine, but for ten years or more it's been grey when inactive.