🔧 Use more robust preview logic

extension.js

@@ -215,18 +215,37 @@ class Extension {
         return;
       }
 
-      // Create a list of all currently enabled effects.
-      const enabledEffects = ALL_EFFECTS.filter(Effect => {
-        return this._settings.get_boolean(`${Effect.getNick()}-close-effect`);
-      });
+      // Now we have to choose an effect.
+      this._effect = null;
 
-      // Nothing is enabled...
-      if (enabledEffects.length == 0) {
-        return;
+      // First we check if an effect is to be previewd.
+      const previewNick = this._settings.get_string('close-preview-effect');
+      if (previewNick != '') {
+        this._effect = ALL_EFFECTS.find(Effect => {
+          return Effect.getNick() == previewNick;
+        });
+
+        // Only preview the effect once.
+        this._settings.set_string('close-preview-effect', '');
+
+      } else {
+
+        // Else we choose a random effect from all enabled effects. Therefore, we first
+        // create a list of all currently enabled effects.
+        const enabled = ALL_EFFECTS.filter(Effect => {
+          return this._settings.get_boolean(`${Effect.getNick()}-close-effect`);
+        });
+
+        // And then choose a random effect.
+        if (enabled.length > 0) {
+          this._effect = enabled[Math.floor(Math.random() * enabled.length)];
+        }
       }
 
-      // Choose a random effect.
-      this._effect = enabledEffects[Math.floor(Math.random() * enabledEffects.length)];
+      // If nothing was enabled, we have to do nothing :)
+      if (this._effect == null) {
+        return;
+      }
 
       // The effect usually will choose to override the present transitions on the actor.
       const transitionConfig = this._effect.getCloseTransition(actor, this._settings);

prefs.js

@@ -297,18 +297,9 @@ var PreferencesDialog = class PreferencesDialog {
 
           // Open the preview window once the preview button is clicked.
           this._button.connect('clicked', () => {
-            // Create a list of all currently enabled effects.
-            const enabledEffects = ALL_EFFECTS.filter(Effect => {
-              return dialog.getSettings().get_boolean(`${Effect.getNick()}-close-effect`);
-            });
 
-            // Disable all enabled effects temporarily.
-            enabledEffects.forEach(Effect => {
-              dialog.getSettings().set_boolean(`${Effect.getNick()}-close-effect`, false);
-            });
-
-            // Enable the to-be-previewed effect.
-            dialog.getSettings().set_boolean(`${Effect.getNick()}-close-effect`, true);
+            // Set the to-be-previewed effect.
+            dialog.getSettings().set_string('close-preview-effect', Effect.getNick());
 
             // Create the preview-window.
             const window = new Gtk.Window({
@@ -344,17 +335,6 @@ var PreferencesDialog = class PreferencesDialog {
             }
 
             window.show();
-
-            // Restore settings when the window gets closed.
-            window.connect('unrealize', () => {
-              // Disable the to-be-previewed effect again.
-              dialog.getSettings().set_boolean(`${Effect.getNick()}-close-effect`, false);
-
-              // Enable all previously enabled effects again.
-              enabledEffects.forEach(Effect => {
-                dialog.getSettings().set_boolean(`${Effect.getNick()}-close-effect`, true);
-              });
-            });
           });
         }
       });

schemas/org.gnome.shell.extensions.burn-my-windows.gschema.xml

@@ -13,6 +13,12 @@
       <description>Set to true to burn dialogs as well.</description>
     </key>
 
+    <key name="close-preview-effect" type="s">
+      <default>""</default>
+      <summary>Close Preview Effect</summary>
+      <description>The effect with this nick will be used for the next window-close animation.</description>
+    </key>
+
     <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
     <!-- Fire Options                                                                  -->
     <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->