Add config to make close button collapse auto hide dock

Author: Syarif Fakhri

src/DockAreaTitleBar.cpp

@@ -415,7 +415,12 @@ void CDockAreaTitleBar::onTabsMenuAboutToShow()
 void CDockAreaTitleBar::onCloseButtonClicked()
 {
     ADS_PRINT("CDockAreaTitleBar::onCloseButtonClicked");
-	if (d->testConfigFlag(CDockManager::DockAreaCloseButtonClosesTab))
+	if (CDockManager::testAutoHideConfigFlag(CDockManager::AutoHideCloseButtonCollapsesDock) &&
+		d->DockArea->autoHideDockContainer())
+	{
+		d->DockArea->autoHideDockContainer()->collapseView(true);
+	}
+	else if (d->testConfigFlag(CDockManager::DockAreaCloseButtonClosesTab))
 	{
 		d->TabBar->closeTab(d->TabBar->currentIndex());
 	}

src/DockManager.h

@@ -239,6 +239,7 @@ class ADS_EXPORT CDockManager : public CDockContainerWidget
 		AutoHideButtonCheckable = 0x08, //!< If the flag is set, the auto hide button will be checked and unchecked depending on the auto hide state. Mainly for styling purposes.
 		AutoHideSideBarsIconOnly = 0x10,///< show only icons in auto hide side tab - if a tab has no icon, then the text will be shown
 		AutoHideShowOnMouseOver = 0x20, ///< show the auto hide window on mouse over tab and hide it if mouse leaves auto hide container
+		AutoHideCloseButtonCollapsesDock = 0x40, ///< Close button of an auto hide container closes the dock instead of hiding it completely
 
 		DefaultAutoHideConfig = AutoHideFeatureEnabled
 			                  | DockAreaHasAutoHideButton ///< the default configuration for left and right side bars