Currently, Builder relies on “Word Completion” from GtkSourceView. This provides completion of words used within the current, or other open, documents. The project will require to implement a new Word Completion provider that can take into account the distance of the word from the cursor position so that words near the cursor are in predictable locations.
Ideally, this would look similar to Vim’s implementation of Word Completion. Control+P (in Vim mode) would take us to the closest match above the current word. Control+N would take us to the closest match after the cursor.