The dropdown in the toolbar allows you to select which type of reference to insert. The button to the right of the dropdown allows you to refresh the selected references if you make changes to the project such as adding a new image or token file. The Find textbox allows you to search for an item by ID. Tokens, images, and code snippets perform a case-insensitive search for the entered ID and select it if found. For code entities, a regular expression search is performed using all member IDs found in the project's XML comments files and the .NET Framework comments files. To insert a reference from the list into a topic, either double-click it or drag and drop it into the topic. The references that can be inserted are as follows:

Tokens

When this is selected, a list of all tokens grouped by their containing token file is shown. In order to be listed, the file must have a BuildAction of Tokens. When inserted into a topic, the selected ID is wrapped in a token element.

Images

When this is selected, a list of all conceptual content image files is shown. To appear, the file must have a BuildAction of Image. When inserted into an HTML file, the image reference will be inserted as an HTML img element. When dropped in a MAML topic, a context menu will appear that lets you insert the reference as a mediaLink, mediaLinkInline, or an externalLink element.

Code Snippets

When this is selected, a list of all code snippets grouped by their containing code snippet file is shown. In order to be listed, the file must have a BuildAction of CodeSnippets. When inserted into a topic, the selected ID is wrapped in a codeReference element.

Code Entities

When this is selected, all XML comments files plus the .NET Framework comments files are indexed to obtain a list of possible API members that can be used as code entity references. Due to the large number of elements, they are not listed. Instead, enter some text or a regular expression in the Find textbox and hit Enter to list all members that match the search text.

When inserted into an HTML file, the entity reference will be inserted as an XML comment see element. Note that these will only be resolved to a clickable link if the item references a member found in your code. It will not create links to .NET Framework members in HTML files. When dropped in a MAML topic, the entity reference will be inserted as a codeEntityReference element. When the help file is built, these will be resolved to links that will take you to the help page for that item (i.e. the API member help page for your classes or MSDN Online help pages for .NET Framework members).