You cant edit someone else's content on YouTube, Its not like WikiAnswers.
The difference between list box and combo box is that-:The list box provides the list of items from which the user can select one or more, whereas in the combo box the user can select only one item from it.List boxes come in two styles: standard style and check box style. Combo boxes have three styles: drop down combo, simple combo and drop down list.We cannot edit the item present in the list box during run time, whereas we can edit the item present in the combo box.
If you are referring to a blog entry, Yes! You can edit a blog you published. Just look at the "edit button" and you can make some modifications to your blog entry, to add images, videos and texts.
Edit
A combo box is a list of multiple values a user can select. Sometimes we refer to them as dropdown lists. When you click on it a list of value pops down and you can choose an option. They are very commonly seen on computers. To create them you use the Combo Box control in Visual BASIC.
If you mean the content of the mail, you can't. You can only edit a mail by forwarding or replying.
Wikipedia
Simple. Go to Wikipedia, create a username and password, sign in, go to the article, and click EDIT. Large articles are broken up into sections. Near the top of each section, on the right, is the word EDIT. If you click it, that section will appear in an edit window. If you wish to edit the main entry -- the first few paragraphs at the very top -- click the edit this pagetab.
All editors edit content and grammar of publications. More specifically, a line editor in a publishing house is responsible for the grammar of a book.
Grid Control
You have to click a button!
It changes to Edit mode.