asil4y92:
Yes, the Level Dimension Tool is separate from the Dimension Tool. Look at Work Environment > Tool Schemes > Toolbox to see if the Level Dimension tool is part of your current WE, or change to one of the default WE Profiles.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
David