Fusion seems to require one to click within the workspace to use hotkeys, even if the window already had foucs & the user just completed a command.
Areas I have seen this are projecting surfaces within the sketch environment and assembling components.
For example, this afternoon I am working on joining a number of small plates to the side of a flat tank using the rigid joint command. After completing one joint, I should be able to press "enter" to execute the command, and immediately press "j" to start another joint command. However, I currently must click on the screen & then press "j" for the hotkey to work. This defeats the purpose of the hotkeys and adds needless time to design. I am using Fusion on a 15" Retina Powerbook with OSX 10.11.1.
Please look into this.