Make cursor appear when clicking after the last line of a file (#56)

Sources/CodeEditTextView/STTextViewController.swift

@@ -107,7 +107,7 @@ public class STTextViewController: NSViewController, STTextViewDelegate, ThemeAt
     public override func loadView() {
         textView = STTextView()
 
-        let scrollView = NSScrollView()
+        let scrollView = CEScrollView()
         scrollView.translatesAutoresizingMaskIntoConstraints = false
         scrollView.hasVerticalScroller = true
         scrollView.documentView = textView
@@ -342,3 +342,30 @@ public class STTextViewController: NSViewController, STTextViewDelegate, ThemeAt
         highlighter = nil
     }
 }
+
+class CEScrollView: NSScrollView {
+
+    override func mouseDown(with event: NSEvent) {
+
+        if let textView = self.documentView as? STTextView,
+            !textView.visibleRect.contains(event.locationInWindow) {
+            // If the `scrollView` was clicked, but the click did not happen within the `textView`,
+            // set cursor to the last index of the `textView`.
+
+            guard let provider = textView.textLayoutManager.textContentManager else {
+                return
+            }
+
+            let string = textView.string
+
+            let range = NSRange(string.endIndex..<string.endIndex, in: string)
+            if let newRange = NSTextRange(range, provider: provider) {
+                _ = textView.becomeFirstResponder()
+                textView.setSelectedRange(newRange)
+                return
+            }
+        }
+
+        super.mouseDown(with: event)
+    }
+}