diff --git a/src/StelMainView.cpp b/src/StelMainView.cpp
index 74da53fc0bc92..a33c2e4f6e1e9 100644
--- a/src/StelMainView.cpp
+++ b/src/StelMainView.cpp
@@ -395,17 +395,14 @@ class StelRootItem : public QGraphicsObject
 		//a sanity check
 		Q_ASSERT(mainView->glContext() == QOpenGLContext::currentContext());
 
-		{
-			static int oldViewportWidth, oldViewportHeight;
-			GLint viewport[4] = {};
-			GL(QOpenGLContext::currentContext()->functions()->glGetIntegerv(GL_VIEWPORT, viewport));
-			if(viewport[2] != oldViewportWidth || viewport[3] != oldViewportHeight)
-			{
-				qDebug() << "Early painting: OpenGL viewport size: " << viewport[2] << "x" << viewport[3];
-				oldViewportWidth = viewport[2];
-				oldViewportHeight = viewport[3];
-			}
-		}
+		StelApp& app = StelApp::getInstance();
+
+		// This can change even on the screen even without actual system settings change.
+		// E.g. in KWin 6.1.5 with Wayland backend, if we set 150% scale in System Settings,
+		// the app first gets device pixel ratio of 200%, then the widgets are rescaled to 150%
+		// while the screen still remains at 200%. This is ugly, and shouldn't behave like this,
+		// but the following call seems to be enough to get things working right.
+		app.setDevicePixelsPerPixel(mainView->devicePixelRatioF());
 
 		const double now = StelApp::getTotalRunTime();
 		double dt = now - previousPaintTime;
@@ -421,7 +418,6 @@ class StelRootItem : public QGraphicsObject
 #endif
 
 		//update and draw
-		StelApp& app = StelApp::getInstance();
 		app.update(dt); // may also issue GL calls
 		app.draw();
 		painter->endNativePainting();
diff --git a/src/core/StelApp.cpp b/src/core/StelApp.cpp
index ad574d19de34e..5b17edaa96d29 100644
--- a/src/core/StelApp.cpp
+++ b/src/core/StelApp.cpp
@@ -444,9 +444,8 @@ void StelApp::init(QSettings* conf)
 	gl = QOpenGLContext::currentContext()->functions();
 	confSettings = conf;
 
-	devicePixelsPerPixel = QOpenGLContext::currentContext()->screen()->devicePixelRatio();
-	if (devicePixelsPerPixel>1)
-		qDebug() << "Detected a high resolution device! Device pixel ratio:" << devicePixelsPerPixel;
+	devicePixelsPerPixel = StelMainView::getInstance().devicePixelRatioF();
+	qDebug() << "Initial high-DPI scaling factor:" << devicePixelsPerPixel;
 
 	setScreenFontSize(confSettings->value("gui/screen_font_size", getDefaultGuiFontSize()).toInt());
 	setGuiFontSize(confSettings->value("gui/gui_font_size", getDefaultGuiFontSize()).toInt());
@@ -1387,6 +1386,7 @@ void StelApp::setDevicePixelsPerPixel(qreal dppp)
 	// Check that the device-independent pixel size didn't change
 	if (!viewportEffect && !fuzzyEquals(devicePixelsPerPixel, dppp))
 	{
+		qDebug() << "Changing high-DPI scaling factor from" << devicePixelsPerPixel << "to" << dppp;
 		devicePixelsPerPixel = dppp;
 		StelProjector::StelProjectorParams params = core->getCurrentStelProjectorParams();
 		params.devicePixelsPerPixel = devicePixelsPerPixel;
diff --git a/src/gui/StelGuiItems.cpp b/src/gui/StelGuiItems.cpp
index 28b794274eb88..9c7f1de361528 100644
--- a/src/gui/StelGuiItems.cpp
+++ b/src/gui/StelGuiItems.cpp
@@ -386,7 +386,7 @@ void StelButton::paint(QPainter* painter, const QStyleOptionGraphicsItem*, QWidg
 	 *    rectangles.
 	 *    Our keeping QPixmap alive instead of deleting it on return from this function prevents this.
 	 */
-	const double ratio = QOpenGLContext::currentContext()->screen()->devicePixelRatio();
+	const double ratio = StelApp::getInstance().getDevicePixelsPerPixel();
 	if(scaledCurrentPixmap.isNull() || ratio != scaledCurrentPixmap.devicePixelRatioF())
 	{
 		const auto size = boundingRect().size() * ratio;