ui: fix background color of line number was ignored in stylesheet (issue #1201) (#1202)

src/lib_gui/qt/element/code/QtCodeArea.cpp

@@ -32,6 +32,7 @@
 #include "utility.h"
 #include "utilityApp.h"
 #include "utilityString.h"
+#include "utilityQt.h"
 
 MouseWheelOverScrollbarFilter::MouseWheelOverScrollbarFilter() {}
 
@@ -144,6 +145,9 @@ void QtCodeArea::lineNumberAreaPaintEvent(QPaintEvent* event)
 {
 	QPainter painter(m_lineNumberArea);
 
+	utility::setWidgetBackgroundColor(
+		m_lineNumberArea, ColorScheme::getInstance()->getColor("code/snippet/line_number/background"));
+
 	QTextBlock block = firstVisibleBlock();
 	int blockNumber = block.blockNumber();
 	int top = static_cast<int>(blockBoundingGeometry(block).translated(contentOffset()).top());