A DESCRIPTION OF THE PROBLEM :
The com.sun.glass.ui.monocle.MouseInput class doesn't send the keyboard modifiers in events, which results in being unable to select multiple entries in a ListBox.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Select two components in a ListBox by holding down CTRL.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Selecting two listbox items.
ACTUAL -
Ctrl modifier button isn't registered, so only one listbox item can be selected at once.

CUSTOMER SUBMITTED WORKAROUND :
This is a patch that fixes the issue for http://hg.openjdk.java.net/openjfx/8u-dev/rt

diff -r f2e7f7967966 modules/graphics/src/main/java/com/sun/glass/ui/monocle/MouseInput.java
--- a/modules/graphics/src/main/java/com/sun/glass/ui/monocle/MouseInput.java Sat Apr 21 06:04:00 2018 -0700
+++ b/modules/graphics/src/main/java/com/sun/glass/ui/monocle/MouseInput.java Thu Apr 26 00:39:42 2018 +1200
@@ -87,6 +87,9 @@
         int y = Math.max(0, Math.min(newState.getY(), screen.getHeight() - 1));
         newState.setX(x);
         newState.setY(y);
+ // Gets the keyboard state to be used for keyboard modifiers
+ KeyState keyState = new KeyState();
+ KeyInput.getInstance().getState(keyState);
         // Get the cached window for the old state and compute the window for
         // the new state
         MonocleWindow oldWindow = state.getWindow(false);
@@ -105,7 +108,7 @@
                 MonocleView oldView = (MonocleView) oldWindow.getView();
                 if (oldView != null) {
                     // send exit event
- int modifiers = state.getModifiers(); // TODO: include key modifiers
+ int modifiers = state.getModifiers() | keyState.getModifiers();
                     int button = state.getButton();
                     boolean isPopupTrigger = false; // TODO
                     int oldX = state.getX();
@@ -145,7 +148,7 @@
         int relY = y - window.getY();
         // send enter event
         if (oldWindow != window && view != null) {
- int modifiers = state.getModifiers(); // TODO: include key modifiers
+ int modifiers = state.getModifiers() | keyState.getModifiers();
             int button = state.getButton();
             boolean isPopupTrigger = false; // TODO
             postMouseEvent(view, MouseEvent.ENTER, button,
@@ -156,7 +159,7 @@
         if (oldWindow != window | newAbsoluteLocation) {
             boolean isDrag = !state.getButtonsPressed().isEmpty();
             int eventType = isDrag ? MouseEvent.DRAG : MouseEvent.MOVE;
- int modifiers = state.getModifiers(); // TODO: include key modifiers
+ int modifiers = state.getModifiers() | keyState.getModifiers();
             int button = state.getButton();
             boolean isPopupTrigger = false; // TODO
             postMouseEvent(view, eventType, button,
@@ -173,10 +176,11 @@
                 int button = buttons.get(i);
                 pressState.pressButton(button);
                 // send press event
+ int modifiers = pressState.getModifiers() | keyState.getModifiers();
                 boolean isPopupTrigger = false; // TODO
                 postMouseEvent(view, MouseEvent.DOWN, button,
                                relX, relY, x, y,
- pressState.getModifiers(), isPopupTrigger,
+ modifiers, isPopupTrigger,
                                synthesized);
             }
         }
@@ -191,10 +195,11 @@
                 int button = buttons.get(i);
                 releaseState.releaseButton(button);
                 // send release event
+ int modifiers = releaseState.getModifiers() | keyState.getModifiers();
                 boolean isPopupTrigger = false; // TODO
                 postMouseEvent(view, MouseEvent.UP, button,
                                relX, relY, x, y,
- releaseState.getModifiers(), isPopupTrigger,
+ modifiers, isPopupTrigger,
                                synthesized);
             }
         }
@@ -208,7 +213,7 @@
                 default: dY = 0.0; break;
             }
             if (dY != 0.0) {
- int modifiers = newState.getModifiers();
+ int modifiers = newState.getModifiers() | keyState.getModifiers();
                 RunnableProcessor.runLater(() -> {
                     view.notifyScroll(relX, relY, x, y, 0.0, dY,
                                       modifiers, 1, 0, 0, 0, 1.0, 1.0);

FREQUENCY : always