Don't try to parse or render if we errored before

It catches and displays the exception, but doesn't stop processing.

Author: peace-maker

smxviewer/MainWindow.cs

@@ -50,6 +50,7 @@ private void openToolStripMenuItem_Click(object sender, EventArgs e)
             catch (Exception ex)
             {
                 MessageBox.Show("Could not open file: " + ex.Message, "File error", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                return;
             }
 
             try
@@ -63,6 +64,7 @@ private void openToolStripMenuItem_Click(object sender, EventArgs e)
             catch (Exception ex)
             {
                 MessageBox.Show("Could not parse file: " + ex.Message);
+                return;
             }
 
             renderFile();