diff --git a/package.json b/package.json
index ca6dc735..8b329bb2 100644
--- a/package.json
+++ b/package.json
@@ -3509,6 +3509,12 @@
                     "default": "interpreted",
                     "markdownDescription": "How the analyzer runs. Set from the run-mode button in the status bar and remembered per workspace folder."
                 },
+                "analyzer.dictSource": {
+                    "type": "boolean",
+                    "scope": "resource",
+                    "default": true,
+                    "description": "On DEV runs, have the engine (4.2.33 or later) record which dictionary file and line built each node, so Rule Fired on a parse tree node opens that dictionary entry."
+                },
                 "analyzer.regressionTerminal": {
                     "type": "boolean",
                     "scope": "resource",
diff --git a/src/nlp.ts b/src/nlp.ts
index e27c3c1c..92a43235 100644
--- a/src/nlp.ts
+++ b/src/nlp.ts
@@ -17,6 +17,9 @@ import * as telemetry from './telemetry/telemetry';
 import { analyzerOutputLines, lastTreePass } from './output/analyzerOutput';
 import { generatorChanged, kbOutputsOf } from './session/kbGen';
 
+// First engine with -DICTSOURCE (nlp-engine#432).
+const DICT_SOURCE_ENGINE = '4.2.33';
+
 let analyzerOutputChannel: vscode.OutputChannel | undefined;
 
 /** Show what the analyzer printed with cout() in the "NLP++ Analyzer Output" panel. */
@@ -160,6 +163,15 @@ export class NLPFile extends TextFile {
 				args.push('-COMPILED');
 			}
 			args.push('"' + filestr + '"', devFlagStr);
+			// Nodes built from .dict entries then name the entry's file and line,
+			// so Rule Fired on the tree opens it (#475). Engines before 4.2.33
+			// reject the switch and exit, so it goes only to newer ones.
+			if (mode == DevMode.DEV
+				&& vscode.workspace.getConfiguration('analyzer').get<boolean>('dictSource', true)
+				&& visualText.engineVersion
+				&& visualText.versionCompare(visualText.engineVersion, DICT_SOURCE_ENGINE) >= 0) {
+				args.push('-DICTSOURCE');
+			}
 
 			visualText.nlp.setAnalyzerStatus(filepath, analyzerStatus.ANALYZING);
 
diff --git a/src/treeFile.ts b/src/treeFile.ts
index a72e1c9a..b1bc0943 100644
--- a/src/treeFile.ts
+++ b/src/treeFile.ts
@@ -86,12 +86,34 @@ export class TreeFile extends TextFile {
 
 					// If 0,0, then search inside dictionary files
 				} else if (tline.ruleLine == 0) {
-					this.searchInDictionaries(tline.node);
+					if (!this.openDictSource())
+						this.searchInDictionaries(tline.node);
 				}
 			}
 		}
 	}
 
+	// A run with -DICTSOURCE (engine 4.2.33+) puts the entry that built a
+	// dictionary node on it: ("dictfile" "words.dict") ("dictline" 14).
+	// Open that line rather than searching every dictionary (#475).
+	openDictSource(): boolean {
+		const line = this.getLines()[this.selStartLine] ?? '';
+		const file = /\("dictfile" "([^"]+)"\)/.exec(line);
+		if (!file) return false;
+		const dictPath = path.join(visualText.analyzer.getKBDirectory().fsPath, file[1]);
+		if (!fs.existsSync(dictPath)) return false;
+		const num = /\("dictline" (\d+)\)/.exec(line);
+		const lineNum = num ? parseInt(num[1], 10) : 0;
+		vscode.window.showTextDocument(vscode.Uri.file(dictPath), { viewColumn: vscode.ViewColumn.Beside }).then(edit => {
+			if (lineNum > 0 && lineNum <= edit.document.lineCount) {
+				const entry = edit.document.lineAt(lineNum - 1).range;
+				edit.selections = [new vscode.Selection(entry.start, entry.end)];
+				edit.revealRange(entry, vscode.TextEditorRevealType.InCenter);
+			}
+		});
+		return true;
+	}
+
 	searchInDictionaries(word: string) {
 		const finalMatches: FindItem[] = [];
 		let searchWord = word.toLowerCase();