I use Details... simply so i can order the machine by "computer" (the name of the user) or by the Address "the actual computer name on the domain", so if i know one or the other i can find it quicker. Try "details" as your view instead? Though switching mine TO details doesnt make it lose the size either so I'm really not sure.
I think I know the cause -
On my own screen when I resize and close the application, then reopen, it doesn't lose it's previous size.
Problem is that this is on a lenovo x201 1280x720 screen. When I go to work I plug into a 1920x1200 display, maybe the change in resolution is causing radviewer to default?
That could be, if the window is outside of the available space, for example the height is somewhere between 1280 and 1920, while you are on the larger display, then open it after youve moved to the smaller display, it might just default at that point since it literally cant display it at the previous res. What happens if you go the other way? Smaller res to larger?
The change in res may make it default period, regardless of window size too. Who knows.
The window size is something like 550 high by about 600 wide. Just enough to have a few machines (about 20) in a list.
Never bigger than half a screen wide or high. And that's on the small laptop display.