Good morning Aldevinas,
Sorry for the long delay in answering you but it took more than expected to replicate what your are experiencing and I hope to have figured out your issue.
First be sure to have the same Access Groups in all the companies, than set the user rights up in a way that the User will access to the modules he/she should use, for example: If you want to allow Laura to access to the SL be sure all the companies have the same access groups and than select the access group which allow to access to the SL.
In Technins>>Register: Global Users>>Flip: Companies>>into the matrix fill the field Code with the company you want to give access and in the Access Group the grout which allows to access to SL. If you want to give full access to the user Laura to all the modules in the Company 2 you should specify group per group in a way she will have access to all the moduels.

Best Regard
Giuseppe L.
HansaWorld Team