Search All Open Files command (Edit menu)

EditPlus

Search All Open Files command (Edit menu)
Use this command to replace current partial word with an expanded word found in all open files. This command searches all open files for words which begin with current word, inserts the found word into the active document, or presents a pop-up list if there are more than one matching words.

For example, type "str" and run this command, you can choose from "strcpy", "strcat", "strlen", etc.

Shortcuts
Keys:    Ctrl+F2