Bug 93245 [Dialogs] Error messages show up in two locations in the properties dialog
Force an error message: 1) select a Java project 2) open the properties dialog 3) navigate to Java Compiler>Building 4) enable project specific settings 5) enter a letter into the maximum number of problems field ->the error message shows up at the bottom 6) resize the dialog ->the error message also shows up in the banner
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/DialogMessageArea.java
boolean showingError = false;
        switch (newType) {
        case IMessageProvider.NONE:
            if (newMessage == null)
                restoreTitle();
            else
                showTitle(newMessage, null);
            return;
        case IMessageProvider.INFORMATION:
            newImage = JFaceResources.getImage(Dialog.DLG_IMG_MESSAGE_INFO);
            break;
        case IMessageProvider.WARNING:
            newImage = JFaceResources.getImage(Dialog.DLG_IMG_MESSAGE_WARNING);
            break;
        case IMessageProvider.ERROR:
            newImage = JFaceResources.getImage(Dialog.DLG_IMG_MESSAGE_ERROR);
            showingError = true;
            break;
        }
        messageComposite.setVisible(true);
        titleLabel.setVisible(false);
        
        if (newMessage.equals(messageText.getText())
                && newImage == messageImageLabel.getImage())
            return;
        messageImageLabel.setImage(newImage);
        messageText.setText(newMessage);
        if (showingError)
            setMessageColors(JFaceColors.getErrorBackground(messageComposite
                    .getDisplay()));