fixes issue 2575; fixes issue 2683

nbproject/project.properties

@@ -1,3 +1,4 @@
+build.generated.sources.dir=${build.dir}/generated-sources
 file.reference.fest-assert-1.0a1.jar=lib/fest-assert-1.0a1.jar
 file.reference.fest-reflect-0.4.jar=lib/fest-reflect-0.4.jar
 file.reference.fest-swing-1.0b1.jar=lib/fest-swing-1.0b1.jar

src/com/dmdirc/addons/ui_swing/SwingController.java

@@ -568,6 +568,13 @@ public final class SwingController extends Plugin implements UIController {
                     "Main frame not created. Unable to continue.");
         }
 
+        if (System.getProperty("java.vm.name", "uknown").contains("OpenJDK")) {
+            JOptionPane.showMessageDialog(null, "OpenJDK has known graphical " +
+                    "issues and as such is unsupported by DMDirc.  Please " +
+                    "consider using the official JRE.", "Unsupported JRE",
+                   JOptionPane.WARNING_MESSAGE);
+        }
+
         Main.setUI(this);
     }