Thread:Project:Support desk/Add categories in templates does not apply

I create a template, i.E. MyTemplate with this code: This is the text in MyTemplate.

Now I create page MyPage and insert MyTemplate:

This is my page.

After that I edit MyTemplate and insert a categorie:

This is the text in MyTemplate.

If I now visit MyPage the category is not apply. (Do a refresh in the browser and so on..). Only if I edit "MyPage" and save it (without changes) the category will apply.

Is this correct? But what do I do if my Template is in hundreds of Pages I like to categorize now? Is there a maintaince script or like this to re-read the template and add the new category?