Using the Pick Topic dialog you can choose a topic of the project when you are editing a link using the Editor, when inserting a topic ID using the Editor and in other places such as the Flag dialog.
To configure the Topic ID Picker
In the Editor you can select the check box next to Show link database links and all topic IDs contained in added link databases appear in the list.
In the default configuration a size change is saved. To open the Pick Topic dialog at a specific position, or to not remember a size change, you can right-click somewhere in the Pick Topic dialog except the Filter. In this dialog box you can specify that the topic picker remembers its position and its size.
Use the Filter on top of the topic picker to search for a specific topic. Enter a word of the topic title you are looking for and all topic titles containing this word are listed.