diff --git a/src/vs/workbench/services/themes/common/colorThemeSchema.ts b/src/vs/workbench/services/themes/common/colorThemeSchema.ts
index bfaae07ad34c1876628abcd6415b210c90341305..33ac29c6ff429c6eb2164c4fbfa24836fc4d4ebf 100644
--- a/src/vs/workbench/services/themes/common/colorThemeSchema.ts
+++ b/src/vs/workbench/services/themes/common/colorThemeSchema.ts
@@ -130,12 +130,13 @@ export const tokenColorizationSettingSchema: IJSONSchema = {
 		},
 		fontStyle: {
 			type: 'string',
-			description: nls.localize('schema.token.fontStyle', 'Font style of the rule: One or a combination of \'italic\', \'bold\' and \'underline\''),
+			description: nls.localize('schema.token.fontStyle', 'Font style of the rule: \'italic\', \'bold\' or \'underline\' or a combination. The empty string unsets inherited settings.'),
 			pattern: '^(\\s*\\b(italic|bold|underline))*\\s*$',
-			patternErrorMessage: nls.localize('schema.fontStyle.error', 'Font style must be a combination of \'italic\', \'bold\' and \'underline\''),
+			patternErrorMessage: nls.localize('schema.fontStyle.error', 'Font style must be \'italic\', \'bold\' or \'underline\' or a combination or the empty string.'),
 			defaultSnippets: [{ body: 'italic' }, { body: 'bold' }, { body: 'underline' }, { body: 'italic bold' }, { body: 'italic underline' }, { body: 'bold underline' }, { body: 'italic bold underline' }]
 		}
 	},
+	additionalProperties: false,
 	defaultSnippets: [{ body: { foreground: '${1:#FF0000}', fontStyle: '${2:bold}' } }]
 };
 
@@ -176,7 +177,8 @@ export function tokenColorsSchema(description: string): IJSONSchema {
 					]
 				},
 				settings: tokenColorizationSettingSchema
-			}
+			},
+			additionalProperties: false
 		}
 	};
 }