Follow-up questions to Closed vs. Hidden Web Part - what is the difference? :
- What are possible uses of hiding a web part (having closing) in Sharepoint 2010?
- why isn't unhiding a webpart in a browser possible?
Follow-up questions to Closed vs. Hidden Web Part - what is the difference? :
Possible uses of hiding (closing) web parts can be if the web part is creating problems, is broken/unusable, or behaving badly. Or if the web part isn't needed anymore (like for an annual survey, only done once a year during May), you can hide it when it is not needed anymore. If the web part is not needed at all, and you do not plan on re-using it, you can delete it from the page instead of "closing" it.
You can un-hide web parts by adding "?contents=1" to the end of the URL, which takes you to the Web Part Page Maintenance page. So for instance, say my page is https://mysharepoint.com/users/salarianengineer/default.aspx and I want to un-hide a web part on that page. Add "?contents=1" so that the URL looks like https://mysharepoint.com/users/salarianengineer/default.aspx?contents=1 and you can go in and un-hide the web parts that you want to show.
From the Web Part Page Maintenance page, you can see all web parts on the page. From here, you can put check marks next to the web parts to perform actions. Your options are Close, Reset, Delete, Go Back To Web Part Page, Switch To Personal View. You can see the Web Part Title, the Type of Web Part (imageWebPart, XsltListViewWebPart, etc), and whether it is open on the page or not (yes/no).
Close - You asked about un-hiding (basically, "un-closing") web parts, but this page will show you ALL web parts. So if you have a bunch of web parts that you'd like to close, it is faster to do it from here than going to each web part, opening the menu, and selecting "close"...just put a check into each box and click Close and you're done ;-)
Reset - Resets the web part (default settings, etc).
Delete - Deletes the web part. From here, it goes to the site Recycle Bin, just in case you need to recover it.
I hope this helps ;-)
Another possible use of hiding a web part (I do this all the time), when you are importing a script onto your page via a content editor web part. Hiding the web part includes the script on the page but makes it so the web part cannot be deleted or closed inadvertantly by users.