The behaviour of the EclEmma plug-in can be adjusted in the Eclipse Preferences dialog. Open the dialog from the Window → Preferences menu. EclEmma's settings are located on the page Java → Code Coverage. Or simply type coverage in the filter field.
The Code Coverage preferences page offers the following options.
Whenever a new coverage session becomes active the Coverage view can be automatically shown in the current workbench window. (Default: on)
A new session is created when a coverage launch terminates or a session is imported. This option determines whether the new session should become automatically active, i.e. its result data is shown in the coverage view and in the Java editors. (Default: on)
Coverage session will be available until they are manually deleted in the Coverage view. For frequent test runs it might be more convenient to remove them automatically with the associated launches. (Default: off)
Launching a coverage test with so called in-place instrumentation will modify your original class files and requires a clean build before the next normal launch. Therefore a optional warning dialog can be shown. (Default: on)
Java elements in the various Eclipse views like the Package Explorer might be directly decorated with coverage data from the current session. This can be enabled on the page General → Appearance → Label Decorators. The corresponding entry is Java Code Coverage. (Default: off)
The annotation style for code coverage in editors can be adjusted on the page General → Editors → Text Editors → Annotations. The corresponding entries are: