Start the on-line documentation from the popup menu.

In the bigger window, choose the menu item Edit->Preferences...

In the Preferences Window, click on the diamond next to "Collections" in the column on the left.

In the text box on the right labeled "Default", the text should be:

/pkg/synopsys_1997.01/doc/online/solid/solid.cfg

Change both occurrences of the word "solid" to "synth".

Click on the "Save" button at the bottom of the Preferences window.

A window saying "Save settings between sessions? Doing so will modify your Iview file, removing all comments." Strangely enough, it says this even if you don't have a file called "Iview" in your home directory, which I doubt anyone does. Such confusing UI design. Click Yes.

Another window pops up, saying "Unable to locate defaults file. Creating a new one: <path_to_your_home_directory>/Iview." NOW it figures out that you don't have a file named that already. Bad timing. Click OK.

You now have a file called Iview in your home directory, and the next time you start up Synopsys documentation, the smaller window will be set up to search the Synopsys synthesis documentation.