After some searching I found up to four year old bug reports detailing the same problem. FOUR YEARS! And after months in this bug report I see the devs are simply ignoring or not grasping the problem.
I also did some testing. When expanding the moodlets and doing absolutely nothing, they remain expanded. When I use right click to move, they remain expanded. But when I use left click they collapse so fast before the pie menu comes up. Then on the next sim they instantly collapse even when I dont do anything.
As a comparison the windows for career, relationships and others in the lower right all remain open once opened regardless if we use right or left click anywhere (except the buttons to open them). Which is exactly how moodlets should operate.