KomodoEdit is a free, open source editor based on ActiveStates Komodo IDE and Mozilla/XUL code.

http://www.activestate.com/Products/komodo_ide/edit_features.mhtml

Dita awareness can be added by

• installing the KomodoEdit Dita xpi extension via Tools | Extension manager | Install http://community.activestate.com/komodo-extension/dita
  

or

• download http://docs.oasis-open.org/dita/v1.1/CS01/dtd/ditadtd.zip file and add the contained catalog-dita.xml file to the Edit | Preferences | Languages | XML catologs.

Furthermore, Komodo Edit has a proper search inside (xml) file feature. "Regex" search should be enabled. Regular expression ".*" should be proper to filter the regarding dita files i.e. "indexterm.*oil" Check the KomodoEdit help for further options.

Drag and drop of the open Komodo Edit XML file's tab into Pixwares http://www.xmlmind.com/xmleditor/ ditamap buckets works fine.

regards,