Bug 11863 Update Test Suite action does not allow to remove
What the action actually does is RECREATE the test suite based on the selection in the dialog. I do an update on a test suite which contains X. It is no clear that if I only select Y in the dialog that I'll end up with X being removed. Normally "Update" shows the content of the existing stuff (dir, zip) and allows to modify this. I think renaming the action (and the dialog) to Recreate Test Suite would solve the problem.
org.eclipse.jdt.junit/src/org/eclipse/jdt/junit/wizards/NewTestCaseCreationWizardPage.java
return status;
					}
					if (pack != null && !JavaModelUtil.isVisible(type, pack)) {
						status.setWarning(Messages.getFormattedString("NewTestClassWizPage.warning.class_to_test.interface_not_visible",classToTestName));
						return status;
					}
				}
				fClassToTest= type;
			} catch (JavaModelException e) {
			status.setError(Messages.getString("NewTestClassWizPage.error.class_to_test.not_valid")); 
			}							
		} else {
			status.setError(""); 
		}
		return status;
	}
	static public IType resolveClassNameToType(IJavaProject jproject, IPackageFragment pack, String classToTestName) throws JavaModelException {
		IType type= null;
		if (type == null && pack != null) {
			String packName= pack.getElementName();
			
			if (!pack.isDefaultPackage()) {
				type= JavaModelUtil.findType(jproject, packName, classToTestName);
			}
			
			if (type == null && !"java.lang".equals(packName)) { 
				type= JavaModelUtil.findType(jproject, "java.lang", classToTestName); 
			}
		}