Sometimes you are unable to pick an object up because you are still holding another object: drop the object you're holding on a table and try to pick the other object up.
Also, it may occur that you had moved from a workbench to another without dropping the object you were holding on to the previous workbench.
On a few occasions, you might need to load the simulation from a checkpoint or try it in another browser (we suggest Mozilla Firefox).
The system is designed to only pick up one item at a time. In the image below, notice that player is already holding a lab coat, which is preventing them from picking up more items.

Please do not hesitate to reach out to our support team if you have any questions or are in need of assistance.