Bug 41927 [Dialogs] Selecting in PreferenceDialog generates too many invalid entries
20030825 If you select an entry, close the dialog and then reopen it selecting anotehr entry will result in a "this page has invalid values" although you selected nothing.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferencePage.java
data.widthHint =
				Math.max(
					widthHint,
					defaultsButton.computeSize(
						SWT.DEFAULT,
						SWT.DEFAULT,
						true).x);
			defaultsButton.setLayoutData(data);
			defaultsButton.addSelectionListener(new SelectionAdapter() {
				public void widgetSelected(SelectionEvent e) {
					performDefaults();
				}
			});
			applyButton = new Button(buttonBar, SWT.PUSH);
			applyButton.setText(labels[1]);
			Dialog.applyDialogFont(applyButton);
			data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
			data.heightHint = heightHint;
			data.widthHint =
				Math.max(
					widthHint,
					applyButton.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x);
			applyButton.setLayoutData(data);
			applyButton.addSelectionListener(new SelectionAdapter() {
				public void widgetSelected(SelectionEvent e) {
					performApply();
				}
			});
			applyButton.setEnabled(isValid());
		} else {