notification that the dataset changed needs to happen on the UI thread.

src/com/fsck/k9/K9.java

@@ -155,7 +155,7 @@ public class K9 extends Application
     private static boolean mMeasureAccounts = true;
     private static boolean mCountSearchMessages = true;
     private static boolean mZoomControlsEnabled = false;
-    private static boolean mMobileOptimizedLayout = false; 
+    private static boolean mMobileOptimizedLayout = false;
 
     private static boolean useGalleryBugWorkaround = false;
     private static boolean galleryBuggy;

src/com/fsck/k9/activity/MessageList.java

@@ -788,7 +788,13 @@ public class MessageList
                         mAdapter.markAllMessagesAsDirty();
                         mController.listLocalMessagesSynchronous(mAccount, mFolderName,  mAdapter.mListener);
                         mAdapter.pruneDirtyMessages();
-                        mAdapter.notifyDataSetChanged();
+                        runOnUiThread(new Runnable()
+                        {
+                            public void run()
+                            {
+                                mAdapter.notifyDataSetChanged();
+                            }
+                        });
                     }
 
                 }

src/com/fsck/k9/provider/MessageProvider.java

@@ -484,9 +484,9 @@ public class MessageProvider extends ContentProvider
         }
 
         /* (non-Javadoc)
-         * 
+         *
          * Close the underlying cursor and dereference it.
-         * 
+         *
          * @see android.database.Cursor#close()
          */
         @Override
@@ -508,9 +508,9 @@ public class MessageProvider extends ContentProvider
         }
 
         /* (non-Javadoc)
-         * 
+         *
          * Making sure cursor gets closed on garbage collection
-         * 
+         *
          * @see java.lang.Object#finalize()
          */
         @Override