After installation of Jaspersoft Studio v5.5 Eclipse plugin into Eclipse 4.3.2 the DataAdapter Editor installs itself as the default editor for *.xml files.
It should not install itself as the default editor.
To workaround this go to Window/Preferences and navigate to General/Editors/File Associations
Find *.xml in the File types list and then select the XML Editor in the Associated editors section. Once selected click the Default button and then OK.