# Previewing a Synk document

Clicking the Preview button will compare the source folders and present a panel describing what actions will take place if you click the Run button in the preview window. After previewing the folders, you have the option to modify individual actions or cancel entirely.

Items that are in either of the source folders are displayed in on outline view in the main body of the window. To see the contents of a folder, click the disclosure triangle next to that item.

A default action for each item is created based on the document settings, but you may modify the action by selecting a different one from the drop down menu.

Directories can either have an action selected that is applied to the entire contents of that directory, or the children can be allowed to decide actions for themselves. If an action is defined for an entire directory, its contents will be hidden in the window. To change actions for a subitem of a directory, the directory must be set to "Let Children Decide."

You can click the "Expand All" button to show the entire contents of every subdirectory of the folders, or click "Collapse All" to show only the top level.

If you are only interested in seeing the items which will have a meaningful action applied to them, you can select the "Hide unchanged actions" checkbox.

Once the preview window appears, you can click the Cancel button to prevent copying or removing any items. If you click the Run button, the specified actions will be executed.