Hi Carlos,
Indeed, I forget to explain our situation.
We are working on Unreal Engine, so all binaries are added in the lock rules via the cloud interface. So this issue only concerne benaries files.
So when we change something in Unreal, it asks us if we want to checkout the file or if we want to make it writable. If we do so, as long as we don't update the workspace, the status of that file in plastic client is "changed" and it is not lock for other users. But as soon as we update the workspace, the status change to Checked-out and it's lock for everyone.
What I want is to let that file as writable/change without it being locked, except if we manually checkout it.