It is possible to type long comment while creating Advanced Workflow though it should be less then 255 characters

Steps to reproduce:
1. Create any site;
2. Upload any document to it and select it;
3. Press Assign Workflow button;
4. Choose the type of Workflow (any), select some reviewer and type long comment in Comment field (about 1000 symbols), press Assign Workflow button; -> the comment is typed and no notification about it's length appears, though in My Tasks dashlet only first 255 characters of this comment are displayed;

Expected result:
Should be a restriction for 255 symbols.