Tab change really slow on VM

When I run TC11 on a virtual machine having the Project files on a Network share,

changing from one code Editor tab to another takes about 3 seconds, if the Tabs belong to different Projects of the same Project Suite.

Changing Tabs inside a Project is fast.

Changing Tabs on my Office pc is also fast (using the same sources on the Network share), well, Fast.. it does take one second.

???????

Anybody knows how to fix this?