fix positioning of multi-screen support

Author: comtel2000

fx-onscreen-keyboard/src/main/java/org/comtel2000/keyboard/control/KeyBoardPopup.java

@@ -260,7 +260,17 @@ public void setVisible(final Visibility visible, final TextInputControl textNode
       }
 
       Bounds textNodeBounds = textNode.localToScreen(textNode.getBoundsInLocal());
-      Rectangle2D screenBounds = Screen.getPrimary().getVisualBounds();
+      // Find the screen that contains the text input control
+      Rectangle2D screenBounds =
+          Screen.getScreensForRectangle(
+                  textNodeBounds.getMinX(),
+                  textNodeBounds.getMinY(),
+                  textNodeBounds.getWidth(),
+                  textNodeBounds.getHeight())
+              .stream()
+              .map(Screen::getVisualBounds)
+              .findFirst()
+              .orElse(Screen.getPrimary().getVisualBounds());
       if (textNodeBounds.getMinX() + getWidth() > screenBounds.getMaxX()) {
         setX(screenBounds.getMaxX() - getWidth());
       } else {