Closes #232

src/Squidex/app/framework/angular/indeterminate-value.directive.ts

@@ -41,7 +41,9 @@ export class IndeterminateValueDirective implements ControlValueAccessor {
     public writeValue(value: boolean | number | undefined) {
         if (!Types.isBoolean(value)) {
             this.renderer.setElementProperty(this.element.nativeElement, 'indeterminate', true);
+            this.renderer.setElementProperty(this.element.nativeElement, 'checked', false);
         } else {
+            this.renderer.setElementProperty(this.element.nativeElement, 'indeterminate', false);
             this.renderer.setElementProperty(this.element.nativeElement, 'checked', value);
         }
     }

src/Squidex/app/shared/services/schemas.fields.spec.ts

@@ -127,12 +127,12 @@ describe('BooleanField', () => {
         expect(field.formatValue(null)).toBe('');
     });
 
-    it('should format to checkmark if true', () => {
-        expect(field.formatValue(true)).toBe('✔');
+    it('should format to Yes if true', () => {
+        expect(field.formatValue(true)).toBe('Yes');
     });
 
-    it('should format to minus if false', () => {
-        expect(field.formatValue(false)).toBe('-');
+    it('should format to No if false', () => {
+        expect(field.formatValue(false)).toBe('No');
     });
 
     it('should return default value for default properties', () => {

src/Squidex/app/shared/services/schemas.service.ts

@@ -525,7 +525,7 @@ export class BooleanFieldPropertiesDto extends FieldPropertiesDto {
             return '';
         }
 
-        return value ? '✔' : '-';
+        return value ? 'Yes' : 'No';
     }
 
     public createValidators(isOptional: boolean): ValidatorFn[] {