remove focus from exam start button in exam mode

Author: FreekBes

client/uis/screen.ts

@@ -59,7 +59,10 @@ export abstract class UIScreen {
 		if (!this._formShown) {
 			this._formShown = true;
 			this._form.form.style.display = "block";
-			this._getInputToFocusOn().focus();
+			const inputToFocusOn = this._getInputToFocusOn();
+			if (inputToFocusOn !== null) {
+				inputToFocusOn.focus();
+			}
 			this._connectEvents();
 		}
 	}
@@ -85,7 +88,7 @@ export abstract class UIScreen {
 
 	protected abstract _initForm(): void;
 	protected abstract _wigglePasswordInput(): void;
-	protected abstract _getInputToFocusOn(): HTMLInputElement | HTMLButtonElement;
+	protected abstract _getInputToFocusOn(): HTMLInputElement | HTMLButtonElement | null;
 	protected abstract _enableOrDisableSubmitButton(): boolean;
 
 	/**

client/uis/screens/examscreen.ts

@@ -162,7 +162,8 @@ export class ExamModeUI extends UIScreen {
 		console.error(message);
 	}
 
-	protected _getInputToFocusOn(): HTMLButtonElement {
-		return (this._form as UIExamModeElements).examStartButton;
+	protected _getInputToFocusOn(): HTMLButtonElement | null {
+		return null; // Don't focus on any input field, there are none.
+		// There is a button we could focus on but then pressing enter/space will trigger the button even when the display is blanking
 	}
 }