Add verify before executing (#70)

(cherry picked from commit 15496be)

Author: RealSilverMoon

src/main/java/com/cleanroommc/modularui/screen/ModularPanel.java

@@ -318,6 +318,7 @@ public boolean onMousePressed(int mouseButton) {
                 return true;
             } else {
                 for (LocatedWidget widget : this.hovering) {
+                    if (widget.getElement() == null || !widget.getElement().isValid()) continue;
                     widget.applyMatrix(getContext());
                     IWidget w = widget.getElement();
                     if (w instanceof IDragResizeable resizeable && widget.getAdditionalHoverInfo() instanceof ResizeDragArea dragArea) {
@@ -423,6 +424,7 @@ public boolean onMouseRelease(int mouseButton) {
             boolean tryTap = this.mouse.tryTap(mouseButton);
             // first see if the clicked widget is still hovered and try to interact with it
             for (LocatedWidget widget : this.hovering) {
+                if (widget.getElement() == null || !widget.getElement().isValid()) continue;
                 if (this.mouse.isWidget(widget)) {
                     if (widget.getElement() instanceof Interactable interactable &&
                             onMouseRelease(mouseButton, tryTap, widget, interactable)) {
@@ -434,8 +436,8 @@ public boolean onMouseRelease(int mouseButton) {
             }
             // now try all other hovered
             for (LocatedWidget widget : this.hovering) {
-                if (!this.mouse.isWidget(widget) && widget.getElement() instanceof Interactable interactable &&
-                        onMouseRelease(mouseButton, tryTap, widget, interactable)) {
+                if (widget.getElement() == null || !widget.getElement().isValid()) continue;
+                if (!this.mouse.isWidget(widget) && widget.getElement() instanceof Interactable interactable && onMouseRelease(mouseButton, tryTap, widget, interactable)) {
                     return true;
                 }
             }
@@ -484,6 +486,7 @@ public boolean onKeyPressed(char typedChar, int keyCode) {
             LocatedWidget pressed = null;
             boolean result = false;
             for (LocatedWidget widget : this.hovering) {
+                if (widget.getElement() == null || !widget.getElement().isValid()) continue;
                 if (widget.getElement() instanceof Interactable interactable) {
                     widget.applyMatrix(getContext());
                     Interactable.Result interactResult = interactable.onKeyPressed(typedChar, keyCode);
@@ -603,7 +606,8 @@ public boolean onMouseDrag(int mouseButton, long timeSinceClick) {
             if (this.mouse.held &&
                     mouseButton == this.mouse.lastButton &&
                     this.mouse.lastPressed != null &&
-                    this.mouse.lastPressed.getElement() instanceof Interactable interactable) {
+                    this.mouse.lastPressed.getElement() instanceof Interactable interactable &&
+            this.mouse.lastPressed.getElement().isValid()) {
                 this.mouse.lastPressed.applyMatrix(getContext());
                 interactable.onMouseDrag(mouseButton, timeSinceClick);
                 this.mouse.lastPressed.unapplyMatrix(getContext());
@@ -617,7 +621,7 @@ public boolean onMouseDrag(int mouseButton, long timeSinceClick) {
     private <T, W extends IWidget & IFocusedWidget & Interactable> T interactFocused(Function<W, T> function, T defaultValue) {
         LocatedWidget focused = this.getContext().getFocusedWidget();
         T result = defaultValue;
-        if (focused.getElement() instanceof Interactable interactable) {
+        if (focused.getElement() instanceof Interactable interactable && focused.getElement().isValid()) {
             focused.applyMatrix(getContext());
             result = function.apply((W) interactable);
             focused.unapplyMatrix(getContext());