fix an issue where the textview is not scrollable after the app goes into background and goes back in foreground.

Session/Conversations/ConversationVC.swift

@@ -441,6 +441,12 @@ final class ConversationVC : BaseVC, ConversationViewModelDelegate, OWSConversat
         mediaCache.removeAllObjects()
     }
     
+    override func appDidBecomeActive(_ notification: Notification) {
+        // This is a workaround for an issue where the textview is not scrollable
+        // after the app goes into background and goes back in foreground.
+        self.snInputView.text = self.snInputView.text
+    }
+    
     deinit {
         NotificationCenter.default.removeObserver(self)
     }

Session/Shared/BaseVC.swift

@@ -25,6 +25,7 @@ class BaseVC : UIViewController {
     override func viewDidLoad() {
         setNeedsStatusBarAppearanceUpdate()
         NotificationCenter.default.addObserver(self, selector: #selector(handleAppModeChangedNotification(_:)), name: .appModeChanged, object: nil)
+        NotificationCenter.default.addObserver(self, selector: #selector(appDidBecomeActive(_:)), name: .OWSApplicationDidBecomeActive, object: nil)
     }
     
     internal func ensureWindowBackground() {
@@ -105,6 +106,10 @@ class BaseVC : UIViewController {
         NotificationCenter.default.removeObserver(self)
     }
     
+    @objc func appDidBecomeActive(_ notification: Notification) {
+        // To be implemented
+    }
+
     override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
         if #available(iOS 13.0, *) {
             SNLog("Current trait collection: \(UITraitCollection.current), previous trait collection: \(previousTraitCollection)")