Where to add ToolkitScriptManager to enable TextBoxWatermarkExtender

Hello,

I'm trying to improve user experience on few components : cart, newletterbox...
I was adding ToolkitScriptManager and TextBoxWatermarkExtender on NewsLetterSubscriptionBoxControl but I have a bug when loading a product page, because a ToolkitScriptManager has already been used for TabContainer.

If I remove my ToolkitScriptManager, I have another bug when loading home page because no ToolkitScriptManager has been found.

I tried to use ScriptManagerProxy but compiler cannot find it...
I tried to find ToolkitScriptManagerProxy but it seems it does not exists...

Would it be a good solution to put one ToolkitScriptManager on the root master page, and remove all references of ToolkitScriptManager in pages and controls?

Thanks,

Correct, put one ToolkitScriptManager on the root master page, and remove all references of ToolkitScriptManager in other pages. But keep in mind that it'll increase page size on all pages of your site

Thanks for your answer.

Do you mean ToolkitScriptManager will not load it's scripts from browser cache, like jQuery, but each page would have to load his own script?