There is no such feature because in general, the idea is to keep the product free of clutter and unnecessary options. However, what you're proposing is easy to accomplish.
Since Quotes is a streaming tool, it honors the
Market Manager settings. If your Streaming provider supports the Market Manager, you can configure the MM and streaming quotes will stop outside trading hours. To do that:
1) make sure your streaming provider supports the MM
2) create a new market in the MM
3) in its Properties, set Open and Close times accordingly
4) finally, add your symbol(s) to the Symbols list (don't forget to apply changes).
If the MM isn't supported, then adding support to an
intraday data provider should be pretty effortless for its developer:
Supporting Market Manager in Custom Data Providers. For providers limited to EOD data, it usually does not make great sense to do so (and for this reason, MS123 won't support the MM in
most EOD-only providers like Yahoo).