The Display and Editing tool in the Score menu displays various options for display and editing including:

• Display in concert pitch: this option can be independent for each view.
• Show hidden notes and symbols: this option allows you to toggle the display of hidden notes and symbols. When unhidden, these objects are shown in grey.
• View pages in column: this controls the orientation of the pages as either vertical or horizontal. 
• Display system divider: shows system dividers while in score view. The divider markers are visible on export to PDF. 
• Keep system breaks in parts: with this option, the page layout of parts will keep the same system breaks as defined in the score page layout.
• Disable multimeasure rests in parts: this option will disable multimeasure rests in parts.
• Keep system margins during editing: by default, as you create and update your score, the layout engine will progressively adjust the layout of staves and systems so that spacing is clean and no overlap of symbols occurs. You can disable this by checking this checkbox. With this option enabled, you can then manually adjust the layout of systems and staves, and Compose won’t readjust them anymore.  Use this option when you want to keep full control of the page layout of systems and staves.
• Rebuild part: this button is active only when in part view and will force Compose to recompute the page layout of that part, taking into account some of the above options.