Limit pcmanfm-qt's transparency hack to its main window

Kvantum/ChangeLog

@@ -13,6 +13,7 @@ V1.0.0
  * Added a workaround for KWin-Wayland's menus and tooltips (they're polished before the platform name is set to "wayland").
  * Added an option (to Kvantum Manager) for not blurring inactive windows.
  * Removed the workaround fo the fixed Qt5 bug QTBUG-47043 but added another workaround for a similar Qt6 bug.
+ * Limit the transparency of PCManFM-Qt's view to its main window.
 
 V0.20.2
 ---------

Kvantum/NEWS

@@ -1,5 +1,5 @@
 Latest version:
 
-	4 Dec 2021, V1.0.0
+	12 Dec 2021, V1.0.0
 
 See "ChangeLog" for changes.

Kvantum/style/Kvantum.cpp

@@ -3308,7 +3308,8 @@ void Style::drawPrimitive(QStyle::PrimitiveElement element,
                                                                : QPalette::Active,
                                                              QPalette::Base));
                 }
-                else break;
+                else if (qobject_cast<QMainWindow*>(pw->window()))
+                  break;
               }
               else if (hspec_.transparent_pcmanfm_sidepane && pw->inherits("Fm::SidePane"))
               {

Kvantum/style/polishing.cpp

@@ -563,7 +563,8 @@ void Style::polish(QWidget *widget)
     QWidget *gp = getParent(widget,2);
     if ((hspec_.transparent_pcmanfm_view
          && widget->autoFillBackground()
-         && (gp && gp->inherits("Fm::FolderView") && !gp->inherits("PCManFM::DesktopWindow")))
+         && (gp && gp->inherits("Fm::FolderView") && !gp->inherits("PCManFM::DesktopWindow")
+             && qobject_cast<QMainWindow*>(gp->window())))
         || (hspec_.transparent_pcmanfm_sidepane
             && ((pw && pw->inherits("Fm::DirTreeView"))
                 || (gp && gp->inherits("Fm::SidePane")))))