Show a warning on HiDPI mode auto-switch with a link to the troubleshooting guide.

platform/platform-impl/src/com/intellij/ide/SystemHealthMonitor.java

@@ -41,6 +41,7 @@ import com.intellij.ui.awt.RelativePoint;
 import com.intellij.util.JdkBundle;
 import com.intellij.util.SystemProperties;
 import com.intellij.util.TimeoutUtil;
+import com.intellij.util.ui.UIUtil;
 import com.sun.jna.Library;
 import com.sun.jna.Memory;
 import com.sun.jna.Native;
@@ -78,6 +79,7 @@ public class SystemHealthMonitor implements ApplicationComponent {
     checkReservedCodeCacheSize();
     checkIBus();
     checkSignalBlocking();
+    checkHiDPIMode();
     startDiskSpaceMonitoring();
   }
 
@@ -166,6 +168,14 @@ public class SystemHealthMonitor implements ApplicationComponent {
     }
   }
 
+  private void checkHiDPIMode() {
+    // if switched from JRE-HiDPI to IDE-HiDPI
+    boolean switchedHiDPIMode = SystemInfo.isJetBrainsJvm && "true".equalsIgnoreCase(System.getProperty("sun.java2d.uiScale.enabled")) && !UIUtil.isJreHiDPIEnabled();
+    if (SystemInfo.isWindows && (switchedHiDPIMode || RemoteDesktopService.isRemoteSession())) {
+      showNotification(new KeyHyperlinkAdapter("ide.set.hidpi.mode"));
+    }
+  }
+
   private void showNotification(KeyHyperlinkAdapter adapter, Object... params) {
     @PropertyKey(resourceBundle = "messages.IdeBundle") String key = adapter.key;
     boolean ignored = adapter.isIgnored();

platform/platform-resources-en/src/messages/IdeBundle.properties

@@ -538,6 +538,7 @@ ide.restart.required.notification=<a href="#">{0}</a> {1} to activate changes in
 ide.restart.action=Restart
 ide.shutdown.action=Shutdown
 ide.postpone.action=Postpone
+ide.set.hidpi.mode=You may need to manually configure the HiDPI mode to prevent UI scaling issues. See the <a href="https://intellij-support.jetbrains.com/hc/en-us/articles/115001260010">troubleshooting</a> guide.
 title.plugins=Plugins
 title.plugins.changed=Plugins Changed
 plugin.status.not.specified=(not specified)