Fixes #12887

src/vs/editor/common/controller/cursorWordOperations.ts

@@ -384,20 +384,20 @@ export class WordOperations {
 	public static word(config: CursorConfiguration, model: ICursorSimpleModel, cursor: SingleCursorState, inSelectionMode: boolean, position: Position): SingleCursorState {
 		const wordSeparators = getMapForWordSeparators(config.wordSeparators);
 		let prevWord = WordOperations._findPreviousWordOnLine(wordSeparators, model, position);
-		let isInPrevWord = (prevWord && prevWord.wordType === WordType.Regular && prevWord.start < position.column - 1 && position.column - 1 <= prevWord.end);
 		let nextWord = WordOperations._findNextWordOnLine(wordSeparators, model, position);
-		let isInNextWord = (nextWord && nextWord.wordType === WordType.Regular && nextWord.start < position.column - 1 && position.column - 1 <= nextWord.end);
 
 		if (!inSelectionMode) {
 			// Entering word selection for the first time
+			const isTouchingPrevWord = (prevWord && prevWord.wordType === WordType.Regular && prevWord.start <= position.column - 1 && position.column - 1 <= prevWord.end);
+			const isTouchingNextWord = (nextWord && nextWord.wordType === WordType.Regular && nextWord.start <= position.column - 1 && position.column - 1 <= nextWord.end);
 
 			let startColumn: number;
 			let endColumn: number;
 
-			if (isInPrevWord) {
+			if (isTouchingPrevWord) {
 				startColumn = prevWord.start + 1;
 				endColumn = prevWord.end + 1;
-			} else if (isInNextWord) {
+			} else if (isTouchingNextWord) {
 				startColumn = nextWord.start + 1;
 				endColumn = nextWord.end + 1;
 			} else {
@@ -419,13 +419,16 @@ export class WordOperations {
 			);
 		}
 
+		const isInsidePrevWord = (prevWord && prevWord.wordType === WordType.Regular && prevWord.start < position.column - 1 && position.column - 1 < prevWord.end);
+		const isInsideNextWord = (nextWord && nextWord.wordType === WordType.Regular && nextWord.start < position.column - 1 && position.column - 1 < nextWord.end);
+
 		let startColumn: number;
 		let endColumn: number;
 
-		if (isInPrevWord) {
+		if (isInsidePrevWord) {
 			startColumn = prevWord.start + 1;
 			endColumn = prevWord.end + 1;
-		} else if (isInNextWord) {
+		} else if (isInsideNextWord) {
 			startColumn = nextWord.start + 1;
 			endColumn = nextWord.end + 1;
 		} else {

src/vs/editor/test/browser/controller/cursor.test.ts

@@ -1802,6 +1802,21 @@ suite('Editor Controller - Regression tests', () => {
 		model.dispose();
 	});
 
+	test('issue #12887: Double-click highlighting separating white space', () => {
+		let model = createTextModel(
+			[
+				'abc def'
+			].join('\n')
+		);
+
+		withTestCodeEditor(null, { model: model }, (editor, cursor) => {
+			CoreNavigationCommands.WordSelect.runCoreEditorCommand(cursor, { position: new Position(1, 5) });
+			assert.deepEqual(cursor.getSelection(), new Selection(1, 5, 1, 8));
+		});
+
+		model.dispose();
+	});
+
 	test('issue #9675: Undo/Redo adds a stop in between CHN Characters', () => {
 		usingCursor({
 			text: [