I just saw that if you play a game and while it's happening you go back to the main screen and see some things on the Loadout screen ( like how your Morphling is beautiful with all those shiny beautiful poney rainbow gangnam style items) you get a huge FPS drop.
You will say "Right. I'll see this later. *Close* (or Back)".

Then after the game ends, everyone is happy (not on the dire side), if you decide to go to the Loadout screen again and start looking at the heroes, even if you press "Back", it will be like if you're still looking at the hero.

Like Morphling for example, he gives me a lot of FPS drop when I try to put some items on him. And even when I close, it's very visible that my FPS dropped like 15fps and it keeps going down ( IT'S GOING DOWN. Shinoda, Mike).

I don't really know why it happens, it is like if I open 1000 new tabs on my internet browser with DOTA2, and CS:GO running too. Even I close CS:GO and all the tabs, DOTA2 will be the same way as before.

I saw some people complaining about random spikes and etc. I think this is the cause: The Loadout Hero Screen never closes, it keeps open with the latest hero you've selected. It only stops when you close DOTA2 client.

Here are some screens I got right now: