Our native consoles always exclusively grab the mouse/keyboard when you're interacting with the VM. The only way to get the focus back to your host is to use the ungrab hot key (ie Ctrl+Alt by default), or if you have Tools installed properly you can move the mouse outside the VM console area and it should automatically ungrab and give the focus back to your host.
On ESXi/vSphere, the VMRC native consoles work the same way as the local Workstation consoles in this regard, but you can also access VMs via a web-browser using our WebMKS consoles. Those do allow you to interact with the VM without exclusively grabbing input, because web browsers don't support exclusive input access the same way.
I can't tell if what you're describing is the WebMKS behavior on ESXi, or if the automatic grab/ungrab when you move the mouse in/out of the VM window isn't working for you?
If the automatic grab/ungrab isn't working, but you have tools installed, I'd check your "Gaming Mouse" mode in the UI Input preferences, and try setting it to "Never" instead of "Automatic" and see if that helps.
If you're looking for the WebMKS behavior on Workstation, we don't currently support that. If you're desperate, there's some config option hacks that enable something similar as an experimental mode, but it was so broken we couldn't expose it in the UI and I'm not sure what state it was in for WS 12.
