Gui: Restore previous width when closing task dialog

This fixes #11016

src/Gui/MainWindow.cpp

@@ -599,9 +599,17 @@ bool MainWindow::setupTaskView()
 {
     // Task view
     if (d->hiddenDockWindows.find("Std_TaskView") == std::string::npos) {
+        // clang-format off
+        auto group = App::GetApplication().GetUserParameter()
+                      .GetGroup("BaseApp")
+                     ->GetGroup("Preferences")
+                     ->GetGroup("DockWindows")
+                     ->GetGroup("TaskView");
+        // clang-format on
         auto taskView = new Gui::TaskView::TaskView(this);
-        taskView->setObjectName
-            (QString::fromLatin1(QT_TRANSLATE_NOOP("QDockWidget","Tasks")));
+        bool restore = group->GetBool("RestoreWidth", taskView->shouldRestoreWidth());
+        taskView->setRestoreWidth(restore);
+        taskView->setObjectName(QString::fromLatin1(QT_TRANSLATE_NOOP("QDockWidget","Tasks")));
         taskView->setMinimumWidth(210);
 
         DockWindowManager* pDockMgr = DockWindowManager::instance();

src/Gui/TaskView/TaskView.cpp

@@ -27,6 +27,7 @@
 # include <QActionEvent>
 # include <QApplication>
 # include <QCursor>
+# include <QDockWidget>
 # include <QLineEdit>
 # include <QPointer>
 # include <QPushButton>
@@ -558,6 +559,7 @@ void TaskView::showDialog(TaskDialog *dlg)
 
     ActiveDialog->open();
 
+    saveCurrentWidth();
     getMainWindow()->updateActions();
 
     triggerMinimumSizeHint();
@@ -602,6 +604,7 @@ void TaskView::removeDialog()
         delete remove;
     }
 
+    tryRestoreWidth();
     triggerMinimumSizeHint();
 }
 
@@ -713,6 +716,34 @@ void TaskView::addTaskWatcher()
     taskPanel->setScheme(QSint::FreeCADPanelScheme::defaultScheme());
 }
 
+void TaskView::saveCurrentWidth()
+{
+    if (shouldRestoreWidth()) {
+        if (auto parent = qobject_cast<QDockWidget*>(parentWidget())) {
+            currentWidth = parent->width();
+        }
+    }
+}
+
+void TaskView::tryRestoreWidth()
+{
+    if (shouldRestoreWidth()) {
+        if (auto parent = qobject_cast<QDockWidget*>(parentWidget())) {
+            Gui::getMainWindow()->resizeDocks({parent}, {currentWidth}, Qt::Horizontal);
+        }
+    }
+}
+
+void TaskView::setRestoreWidth(bool on)
+{
+    restoreWidth = on;
+}
+
+bool TaskView::shouldRestoreWidth() const
+{
+    return restoreWidth;
+}
+
 void TaskView::removeTaskWatcher()
 {
     // In case a child of the TaskView has the focus and get hidden we have

src/Gui/TaskView/TaskView.h

@@ -163,6 +163,10 @@ public:
 
     QSize minimumSizeHint() const override;
 
+    // Restore width before opening a task panel
+    void setRestoreWidth(bool on);
+    bool shouldRestoreWidth() const;
+
 Q_SIGNALS:
     void taskUpdate();
 
@@ -175,6 +179,8 @@ protected Q_SLOTS:
 private:
     void triggerMinimumSizeHint();
     void adjustMinimumSizeHint();
+    void saveCurrentWidth();
+    void tryRestoreWidth();
 
 protected:
     void keyPressEvent(QKeyEvent* event) override;
@@ -199,6 +205,8 @@ protected:
     QSint::ActionPanel* taskPanel;
     TaskDialog *ActiveDialog;
     TaskEditControl *ActiveCtrl;
+    bool restoreWidth = false;
+    int currentWidth = 0;
 
     Connection connectApplicationActiveDocument;
     Connection connectApplicationDeleteDocument;