un: disallow closing in progress; unfocus 'back' button

CleanFlashUninstaller/UninstallForm.cs

@@ -121,5 +121,36 @@ namespace CleanFlashUninstaller {
             Clipboard.SetText(failureBox.Text);
             MessageBox.Show("Copied error message to clipboard!", "Clean Flash Installer", MessageBoxButtons.OK, MessageBoxIcon.Information);
         }
+
+        // note: copy pasted from installer; todo: single F for both
+        private void InstallForm_FormClosing(object sender, FormClosingEventArgs e)
+        {
+            bool v1 = true;
+            // if installing
+            // note: msgbox not pauses the process
+            if (installPanel.Visible)
+            {
+                if (v1)
+                {
+                    // hardlock, only force quit process
+                    // follows current design since Back button is disabled
+                    MessageBox.Show("Please, wait until process end", "Clean Flash Installer", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+                    e.Cancel = true;
+                }
+                else
+                // soft alternative, expert mode, todo: better warning of consequences  
+                if (MessageBox.Show("Are you sure you want to interrupt the process ?", "Clean Flash Installer", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.No)
+                {
+                    e.Cancel = true;
+                }
+                else
+                {
+                    // use cases ?
+                    // uninstall, currently not implemented
+                }
+
+                //todo: same for uninstaller: share same F
+            }
+        }
     }
 }