I released two firefox extensions which are "Search in Popup" and "Open in Popup".
As the name says, these extensions use the popup.
Search in Popup
This extension can search selected text in the popup.
The built-in searching feature can search text in an only new tab.
Due to the reason, we need to leave the current tab and move to the another tab to search text.
You can search it quickly to search it in the popup without leaving current page.
https://addons.mozilla.org/en/firefox/addon/search-in-popup/ 
Open in Popup
This extension can open selected text and a link in the popup.
You can choose http or https when you open the link.
Choosing https, you can open a link which is http as https.
However, for safety reasons, you cannot open a link which is https as http and https will be chosen automatically.
You can check a link quickly to open it in the popup without leaving current page.
https://addons.mozilla.org/en/firefox/addon/open-in-popup/ 
These extensions do not require any permissions.
Honestly, we cannot help being anxious when an extension requires the permission like "Access your data" and etc (at least I think so).
You won't have any anxieties of personal information about installing these extensions, you will worry about things that these extensions will be disabled if you worry about something due to progressive release of firefox.
Anyway, I developed these extensions simply just for fun, I hope you will enjoy.
