Bug 137073 [Preferences] Encoding field editor never fires value change events
The class AbstractEncodingFieldEditor never fires VALUE property change events unless the validaty of the value has also changed. I will attach a patch that corrects the problem.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/dialogs/AbstractEncodingFieldEditor.java
otherEncodingButton.setEnabled(enabled);
		if (encodingCombo != null)
			encodingCombo.setEnabled(enabled);
		
	}
	/**
	 * Returns the default encoding for the object being shown.
	 * 
	 * @return the default encoding for the object being shown
	 */
	protected String findDefaultEncoding() {
		return WorkbenchEncoding.getWorkbenchDefaultEncoding();
	}
	/**
	 * Returns the text for the default encoding button.
	 * 
	 * @return the text for the default encoding button
	 */
	protected String defaultButtonText() {
		return NLS.bind(
				IDEWorkbenchMessages.WorkbenchPreference_defaultEncoding,
				defaultEnc);
	}
	/**
	 * Populates the encodings combo. Sets the text based on the selected
	 * encoding. If there is no selected encoding, the text is set to the
	 * default encoding.
	 * 
	 * @param encodings
	 *            the list of encodings (list of String)