The measure & system control dialog box can be activated by clicking on the Measure & System Control icon.  This is only effective if the score formatting is static.  This can be changed in options.

Controls the number of measures and systems on your score. Only effective if Score Formatting is Static.

Measures per page

You can update the number of measures per system.

Systems per page

You can update the number of systems per page

Scope

This Page

If This Page is selected, your selection will only be executed for the current page you are on.

All Pages

If All Pages is selected, your selection will be executed for your entire score.