@Override
	protected void okCallback() {
		// only close the dialog if the user made valid changes
		try {
			if (applyChanges()) {
				close();
			}
		}
		catch (CancelledException e) {
			// ignore - do not close
		}
	}
This method gets called when the user clicks on the OK Button.  The base
class calls this method.  This method will invoke {@link #applyChanges()} 
and close dialog if that method returns true.  If false is returned, the
{@link #applyChanges()} method should display a status message to indicate
the failure.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/function/AbstractEditFunctionSignatureDialog.java