Note: A Flag can be applied to both sent and received messages in order to mark them as important.
For instance, let’s take a received message.
Go to the message-right –click-menu as directed by the arrow from the figure below.
Select Flag.
Your message is successfully set as the important one with a red-colored flag symbol in it.
To filter the flagged messages from your Chat area.
Go to the Advanced-Data-Filters as directed by the arrow from the figure below.
Select “filter by Flag” to refine the search results of flagged messages.
Find all the filtered flagged messages of your chat area.
Refresh the search results from here as directed by the arrow from the figure below.