popout: fix lifecycle of blur with various popouts

fixes #2901
port 1.5

(cherry picked from commit 93c3030a1e)

quickshell/Common/PopoutManager.qml

@@ -65,16 +65,35 @@ Singleton {
 
     function _openPopout(popout) {
         if (popout.dashVisible !== undefined) {
-            if (popout.dashVisible && !popout.shouldBeVisible && !popout.isClosing)
+            let flagStayedTrue = popout.dashVisible === true;
+            if (popout.dashVisible && !popout.shouldBeVisible && !popout.isClosing) {
                 popout.dashVisible = false;
+                flagStayedTrue = false;
+            }
             popout.dashVisible = true;
+            // Flag already true (e.g. retargeting to another monitor) won't re-fire
+            // the change handler, so drive the surface open explicitly.
+            if (flagStayedTrue)
+                _ensureSurfaceOpen(popout);
             return;
         }
         if (popout.notificationHistoryVisible !== undefined) {
+            const flagStayedTrue = popout.notificationHistoryVisible === true;
             popout.notificationHistoryVisible = true;
+            if (flagStayedTrue)
+                _ensureSurfaceOpen(popout);
             return;
         }
-        popout.open();
+        _ensureSurfaceOpen(popout);
+    }
+
+    function _ensureSurfaceOpen(popout) {
+        if (typeof popout.present === "function") {
+            popout.present();
+            return;
+        }
+        if (typeof popout.open === "function")
+            popout.open();
     }
 
     function _closePopout(popout) {

quickshell/Modules/ControlCenter/ControlCenterPopout.qml

@@ -77,6 +77,12 @@ DankPopout {
 
     readonly property color _containerBg: Theme.nestedSurface
 
+    // Defer open one tick so screen-change geometry settles before the surface
+    // maps; a synchronous open churns the surface and loses the blur on a switch.
+    function present() {
+        Qt.callLater(open);
+    }
+
     function openWithSection(section) {
         StateUtils.openWithSection(root, section);
     }

quickshell/Modules/DankBar/Widgets/ClipboardButton.qml

@@ -63,8 +63,8 @@ BasePill {
         anchors.fill: parent
         acceptedButtons: Qt.LeftButton | Qt.RightButton
         cursorShape: Qt.PointingHandCursor
-        onPressed: mouse => root.triggerRipple(this, mouse.x, mouse.y)
-        onClicked: function (mouse) {
+        onPressed: function (mouse) {
+            root.triggerRipple(this, mouse.x, mouse.y);
             switch (mouse.button) {
             case Qt.RightButton:
                 openContextMenu();

quickshell/Modules/Notifications/Center/NotificationCenterPopout.qml

@@ -61,6 +61,11 @@ DankPopout {
         notificationHistoryVisible = !notificationHistoryVisible;
     }
 
+    // Re-open without toggling the flag (used when retargeting to another monitor).
+    function present() {
+        openSized();
+    }
+
     function openSized() {
         if (!notificationHistoryVisible)
             return;

quickshell/Widgets/DankPopoutStandalone.qml

@@ -79,6 +79,9 @@ Item {
             "rightBar": 0
         })
     property var screen: null
+    // Output the surface binds to; retargeted only in open() while hidden. A live
+    // screen change on a mapped surface loses the popup blur on niri.
+    property var surfaceScreen: null
     readonly property bool frameGapStandaloneActive: CompositorService.frameConfiguredForScreen(screen) && !CompositorService.usesConnectedFrameChromeForScreen(screen)
     readonly property bool fluidStandaloneActive: Theme.isDirectionalEffect
     readonly property bool backgroundDismissWindowRequired: backgroundInteractive
@@ -133,8 +136,6 @@ Item {
     signal popoutClosed
     signal backgroundClicked
 
-    property var _lastOpenedScreen: null
-
     property int effectiveBarPosition: 0
     property real effectiveBarBottomGap: 0
     readonly property string autoBarShadowDirection: {
@@ -338,14 +339,14 @@ Item {
         _frozenMaskWidth = maskWidth;
         _frozenMaskHeight = maskHeight;
 
-        const screenChanged = _lastOpenedScreen !== null && _lastOpenedScreen !== screen;
+        const screenChanged = surfaceScreen !== null && surfaceScreen !== screen;
         if (screenChanged) {
-            // Hide on this tick so Qt actually tears down the wl_surface; the show
-            // gets deferred below so the unmap is processed before the remap.
+            // Unmap before retargeting so the surface is destroyed and recreated
+            // on the new output rather than live-migrated.
             contentWindow.visible = false;
             backgroundWindow.visible = false;
         }
-        _lastOpenedScreen = screen;
+        surfaceScreen = screen;
 
         if (contentContainer && !shouldBeVisible) {
             // Snap morph closed only on a fresh open; on screen-change re-open we stay at 1
@@ -559,7 +560,7 @@ Item {
 
     PanelWindow {
         id: backgroundWindow
-        screen: root.screen
+        screen: root.surfaceScreen
         visible: false
         color: "transparent"
         // Skip buffer updates when there's nothing to render. Briefly flipped
@@ -625,7 +626,7 @@ Item {
 
     PanelWindow {
         id: contentWindow
-        screen: root.screen
+        screen: root.surfaceScreen
         visible: false
         color: "transparent"
         readonly property bool closeVisualActive: root.shouldBeVisible || root.isClosing