[CurrentContainmentActionsModel] Allow making the action about dialog modal

This adjusts the "configure" dialog in the same way as the "about" dialog I fixed in 2f66c0d11c

Differential Revision: https://phabricator.kde.org/D6440

shell/currentcontainmentactionsmodel.cpp

@@ -181,7 +181,7 @@ void CurrentContainmentActionsModel::remove(int row)
     }
 }
 
-void CurrentContainmentActionsModel::showConfiguration(int row)
+void CurrentContainmentActionsModel::showConfiguration(int row, QQuickItem *ctx)
 {
     const QString action = itemData(index(row, 0)).value(ActionRole).toString();
 
@@ -193,7 +193,11 @@ void CurrentContainmentActionsModel::showConfiguration(int row)
     configDlg->setAttribute(Qt::WA_DeleteOnClose);
     QLayout *lay = new QVBoxLayout(configDlg);
     configDlg->setLayout(lay);
-    configDlg->setWindowModality(Qt::WindowModal);
+    if (ctx && ctx->window()) {
+        configDlg->setWindowModality(Qt::WindowModal);
+        configDlg->winId(); // so it creates the windowHandle();
+        configDlg->windowHandle()->setTransientParent(ctx->window());
+    }
 
     Plasma::ContainmentActions *pluginInstance = m_plugins[action];
     //put the config in the dialog

shell/currentcontainmentactionsmodel.h

@@ -56,7 +56,7 @@ public:
     Q_INVOKABLE bool append(const QString &action, const QString &plugin);
     Q_INVOKABLE void update(int row, const QString &action, const QString &plugin);
     Q_INVOKABLE void remove(int row);
-    Q_INVOKABLE void showConfiguration(int row);
+    Q_INVOKABLE void showConfiguration(int row, QQuickItem *ctx = nullptr);
     Q_INVOKABLE void showAbout(int row, QQuickItem *ctx = nullptr);
     Q_INVOKABLE void save();