The document interface on Windows was changed in Acrobat 8 to a single document interface (SDI) which displays each document in a single top-level floating window.
Redax will only function in the multiple document interface (MDI) which can be re-enabled via the preferences panel. Change the preferences by:
- Start Acrobat.
- Choose Edit -> Preferences
- Choose “Documents” from the column on the left side of the dialog window.
- At the top of the Open Settings, uncheck “Show each document in its own window (requires restart).”
- Close and restart Acrobat.