find in selection: do not shrink selection if it is one line

fixes #13621

src/vs/editor/contrib/find/browser/findWidget.ts

@@ -145,7 +145,7 @@ export class FindWidget extends Widget implements IOverlayWidget {
 		this._focusTracker.addFocusListener(() => {
 			this._findInputFocussed.set(true);
 			let selection = this._codeEditor.getSelection();
-			if (selection.endColumn === 1) {
+			if (selection.endColumn === 1 && selection.endLineNumber > selection.startLineNumber) {
 				selection = selection.setEndPosition(selection.endLineNumber - 1, 1);
 			}
 			let currentMatch = this._state.currentMatch;
@@ -504,7 +504,7 @@ export class FindWidget extends Widget implements IOverlayWidget {
 			onChange: () => {
 				if (this._toggleSelectionFind.checked) {
 					let selection = this._codeEditor.getSelection();
-					if (selection.endColumn === 1) {
+					if (selection.endColumn === 1 && selection.endLineNumber > selection.startLineNumber) {
 						selection = selection.setEndPosition(selection.endLineNumber - 1, 1);
 					}
 					if (!selection.isEmpty()) {