Fix a compiler error

I didn't notice the preservation should be put under a condition

extensions/git/src/commands.ts

@@ -230,10 +230,7 @@ export class CommandCenter {
 		}
 
 		if (!left) {
-			const previousVisibleRanges = activeTextEditor.visibleRanges;
-			const document = await workspace.openTextDocument(right);
-			const editor = await window.showTextDocument(document, opts);
-			editor.revealRange(previousVisibleRanges[0]);
+			await commands.executeCommand<void>('vscode.open', right, opts);
 		} else {
 			await commands.executeCommand<void>('vscode.diff', left, right, title, opts);
 		}
@@ -574,16 +571,19 @@ export class CommandCenter {
 				viewColumn: ViewColumn.Active
 			};
 
+			const document = await workspace.openTextDocument(uri);
+
 			// Check if active text editor has same path as other editor. we cannot compare via
 			// URI.toString() here because the schemas can be different. Instead we just go by path.
 			if (activeTextEditor && activeTextEditor.document.uri.path === uri.path) {
+				// preserve not only selection but also visible range
 				opts.selection = activeTextEditor.selection;
-			}
-
 				const previousVisibleRanges = activeTextEditor.visibleRanges;
-			const document = await workspace.openTextDocument(uri);
 				const editor = await window.showTextDocument(document, opts);
 				editor.revealRange(previousVisibleRanges[0]);
+			} else {
+				await window.showTextDocument(document, opts);
+			}
 		}
 	}