ignore arrows events when the textarea is selected

Fixes #1416

ts/components/session/conversation/SessionCompositionBox.tsx

@@ -709,6 +709,9 @@ export class SessionCompositionBox extends React.Component<Props, State> {
       await this.onSendMessage();
     } else if (event.key === 'Escape' && this.state.showEmojiPanel) {
       this.hideEmojiPanel();
+    } else if (event.key === 'PageUp' || event.key === 'PageDown') {
+      // swallow pageUp events if they occurs on the composition box (it breaks the app layout)
+      event.preventDefault();
     }
   }
 

ts/components/session/conversation/SessionConversation.tsx

@@ -307,6 +307,7 @@ export class SessionConversation extends React.Component<Props, State> {
           /> */}
 
         <div
+          // if you change the classname, also update it on onKeyDown
           className={classNames(
             'conversation-content',
             selectionMode && 'selection-mode'
@@ -888,6 +889,7 @@ export class SessionConversation extends React.Component<Props, State> {
       }
       // EXIT WHAT ELSE?
     }
+    if (event.target.classList.contains('conversation-content')) {
       switch (event.key) {
         case 'Escape':
           if (selectionMode) {
@@ -910,6 +912,7 @@ export class SessionConversation extends React.Component<Props, State> {
         default:
       }
     }
+  }
 
   private clearAttachments() {
     this.state.stagedAttachments.forEach(attachment => {