I think I found a glitch in the browser; I'll try to walk through the steps as best I can.
1. Create a subassembly within an assembly, adding constraints between the subassembly and the main assembly components.
2. Within the subassembly, create a new folder in the browser. The folder appears by default under the greyed-out constraints created in the previous step.
3. I cannot drag components into the folder. If I move the folder to the other side of the greyed-out constraints, next to the components, I can then place components into the folder.
This glitch I'm encountering isn't horribly significant, but I thought I'd share and see if anyone else can replicate the issue.
Inventor 2014
HP Pavilion dv6t-6b00
Intel Core i7 2670QM
AMD Radeon HD 6490M
16gb RAM
Windows 7 64 bit
3Dconnexion SpaceExplorer