Fixed cmd/ctrl+X misbehaviour in the extension

Change-Id: I071abfb0278c12bb6a24059b8b9324e64eab79af

Author: mike-lischke

gui/extension/src/WebviewProviders/webview-helpers.ts

@@ -198,6 +198,13 @@ export const prepareWebviewContent = (panel: WebviewPanel, url: URL): void => {
         }, "*");
     });
 
+    document.addEventListener("cut", (event) => {
+        frame.contentWindow.postMessage({
+            source: "host",
+            command: "cut",
+        }, "*");
+    });
+
     window.addEventListener('message', (event) => {
         if (!frame) {
             vscode = acquireVsCodeApi();

gui/frontend/src/supplement/Requisitions.ts

@@ -803,6 +803,13 @@ export class RequisitionHub {
                 element.dispatchEvent(pasteEvent);
             }
 
+            return;
+        } else if (message.command === "cut") {
+            const element = document.activeElement;
+            if (element && (element instanceof HTMLInputElement || element instanceof HTMLTextAreaElement)) {
+                element.dispatchEvent(new ClipboardEvent("cut"));
+            }
+
             return;
         }