src: Fixes for release

* clear references count when clearing code view
* fixed scrolling to character in overview lists
* fixed aggregation activation shown in history menu
* fixed same snippet being added twice
* Sourcetrail [Trial] as window title
* fixed undoing trail expand will always reactivate symbol

src/lib_gui/qt/element/QtCodeFile.cpp

@@ -131,6 +131,16 @@ std::string QtCodeFile::getFileName() const
 
 QtCodeSnippet* QtCodeFile::addCodeSnippet(const CodeSnippetParams& params)
 {
+	for (std::shared_ptr<QtCodeSnippet> snippet : m_snippets)
+	{
+		if (snippet->getStartLineNumber() == params.startLineNumber &&
+			snippet->getEndLineNumber() == params.endLineNumber)
+		{
+			return snippet.get();
+		}
+	}
+
+
 	std::shared_ptr<QtCodeSnippet> snippet(new QtCodeSnippet(params, m_navigator, this));
 
 	if (params.reduced)