Make files visible when searching in `FileBrowser` (#6845)

* Change the title for SideBarWidgets to be vertically centered related to icon and with no underlining

* Update src/gui/SideBarWidget.cpp

Co-authored-by: saker <sakertooth@gmail.com>

* Updating FileBrowser display when searching : showing matching files

* Correcting increment and removing duplicated calls

* Correcting reload tree when filter is activated

---------

Co-authored-by: saker <sakertooth@gmail.com>

include/FileBrowser.h

@@ -75,8 +75,7 @@ public:
 private slots:
 	void reloadTree();
 	void expandItems( QTreeWidgetItem * item=nullptr, QList<QString> expandedDirs = QList<QString>() );
-	// call with item=NULL to filter the entire tree
-	bool filterItems( const QString & filter, QTreeWidgetItem * item=nullptr );
+	bool filterAndExpandItems(const QString & filter, QTreeWidgetItem * item = nullptr);
 	void giveFocusToFilter();
 
 private:
@@ -84,6 +83,9 @@ private:
 
 	void addItems( const QString & path );
 
+	void saveDirectoriesStates();
+	void restoreDirectoriesStates();
+
 	FileBrowserTreeWidget * m_fileBrowserTreeWidget;
 
 	QLineEdit * m_filterEdit;
@@ -99,6 +101,8 @@ private:
 	QCheckBox* m_showFactoryContent = nullptr;
 	QString m_userDir;
 	QString m_factoryDir;
+	QList<QString> m_savedExpandedDirs;
+	QString m_previousFilterValue;
 } ;
 
 
@@ -115,7 +119,6 @@ public:
 	//! that are expanded in the tree.
 	QList<QString> expandedDirs( QTreeWidgetItem * item = nullptr ) const;
 
-
 protected:
 	void contextMenuEvent( QContextMenuEvent * e ) override;
 	void mousePressEvent( QMouseEvent * me ) override;