ui: Fixed search related issues

* select elements when clicking into search bar
* fixed crash and single file mode clearing when fulltext search yields no results

src/lib_gui/qt/view/QtCodeView.cpp

@@ -72,6 +72,11 @@ void QtCodeView::showCodeSnippets(const std::vector<CodeSnippetParams>& snippets
 
 			m_widget->setActiveTokenIds(params.activeTokenIds);
 			m_widget->setErrorInfos(params.errorInfos);
+
+			if (!snippets.size())
+			{
+				m_widget->clearFile();
+			}
 		}
 
 		bool addedFiles = false;