Fix check that editor is in Text tab

Only re-render BrewRenderer when specific props have changed.

Fixes lag during scrolling, which updates the "currentPage" prop, but isn't actually used until the text is changed.

client/homebrew/brewRenderer/brewRenderer.jsx

@@ -1,7 +1,7 @@
 /*eslint max-lines: ["warn", {"max": 300, "skipBlankLines": true, "skipComments": true}]*/
 require('./brewRenderer.less');
 const React = require('react');
-const { useState, useRef, useCallback } = React;
+const { useState, useRef, useCallback, memo } = React;
 const _ = require('lodash');
 
 const MarkdownLegacy = require('naturalcrit/markdownLegacy.js');
@@ -47,7 +47,7 @@ const BrewPage = (props)=>{
 const renderedPages = [];
 let rawPages      = [];
 
-const BrewRenderer = (props)=>{
+const BrewRenderer = memo((props)=>{
 	props = {
 		text                       : '',
 		style                      : '',
@@ -224,6 +224,19 @@ const BrewRenderer = (props)=>{
 			</Frame>
 		</>
 	);
-};
+}, arePropsEqual);
+
+//Only re-render brewRenderer if arePropsEqual == true
+function arePropsEqual(oldProps, newProps) {
+	return (
+		oldProps?.text?.length  === newProps?.text?.length &&
+		oldProps?.style?.length === newProps?.style?.length &&
+		oldProps?.renderer      === newProps?.renderer &&
+		oldProps?.theme         === newProps?.theme &&
+		oldProps?.errors        === newProps?.errors &&
+		oldProps?.themeBundle   === newProps?.themeBundle &&
+		oldProps?.lang          === newProps?.lang
+	);
+}
 
 module.exports = BrewRenderer;

client/homebrew/editor/editor.jsx

@@ -355,7 +355,7 @@ const Editor = createClass({
 	},
 
 	sourceJump : function(targetPage=this.props.currentBrewRendererPageNum, smooth=true){
-		if(!this.isText || isJumping)
+		if(!this.isText() || isJumping)
 			return;
 
 		const textSplit  = this.props.renderer == 'V3' ? /^\\page$/gm : /\\page/;