@Joomla_Direct Yes, Captions is compatible with Joomla 1.5. A new version will also be released this week.
29 June 2012
JCE 184.108.40.206 released
This update fixes a bug introduced in TinyMCE 3.5.4 where SHIFT + A in Chrome would select all content instead of creating an uppercase A.
Check out the Changelog for a full list of bug fixes and updates.
Installation and Updating
Updating to JCE 220.127.116.11 from existing JCE 2.x versions can be done using the JCE Updater, or the Joomla! Update Manager in Joomla! 2.5. Alternatively, follow the Installation Instructions for a new install or update.