Don't show broken composer format bar when selection is whitespace (#8673)

Author: t3chguy

src/components/views/rooms/BasicMessageComposer.tsx

@@ -449,12 +449,11 @@ export default class BasicMessageEditor extends React.Component<IProps, IState>
         const selection = document.getSelection();
         if (this.hasTextSelected && selection.isCollapsed) {
             this.hasTextSelected = false;
-            if (this.formatBarRef.current) {
-                this.formatBarRef.current.hide();
-            }
+            this.formatBarRef.current?.hide();
         } else if (!selection.isCollapsed && !isEmpty) {
             this.hasTextSelected = true;
-            if (this.formatBarRef.current && this.state.useMarkdown) {
+            const range = getRangeForSelection(this.editorRef.current, this.props.model, selection);
+            if (this.formatBarRef.current && this.state.useMarkdown && !!range.text.trim()) {
                 const selectionRect = selection.getRangeAt(0).getBoundingClientRect();
                 this.formatBarRef.current.showAt(selectionRect);
             }