The Rounding coordinates of objects dialog is used to define to which documents the rounding process will be applied.
The dialog is accessed from the schematic editor by clicking Tools » Convert » Round coordinates of objects from the main menus.
Choose Document Scope
Just this document - round coordinates only for the current document.
All schematic documents in the current project - round coordinates for all schematic documents of the current project. Schematic documents of the current project that are currently closed will be opened.
All open schematic documents - round coordinates for all the schematic documents that are currently opened regardless of the project to which they belong.
After you make your selection and click OK, an information dialog will open that summarizes how many objects on how many documents had their coordinates rounded.