diff --git a/src/ed.js b/src/ed.js
index d2f172ec..580f256a 100644
--- a/src/ed.js
+++ b/src/ed.js
@@ -48,7 +48,7 @@
       iconsInSuggestions: false,
       language: 'apl',
       lineHeight: fs + 2,
-      lineNumbers: D.prf.lineNums() ? (x => `[${x - 1}]`) : 'off',
+      lineNumbers: D.prf.lineNums() ? ((x) => `[${x - 1}]`) : 'off',
       matchBrackets: !!D.prf.matchBrackets(),
       minimap: {
         enabled: D.prf.minimapEnabled(),
@@ -68,8 +68,7 @@
       useTabStops: false,
       wordBasedSuggestions: false,
       wordSeparators: D.wordSeparators,
-      unusualLineTerminators: 'off',   // iss646: Prevent message prompt about unusual line endings
-      
+      unusualLineTerminators: 'off', // iss646: Prevent message prompt about unusual line endings
     });
     ed.me = me;
     ed.me_ready = new Promise((resolve) => {
@@ -141,7 +140,7 @@
       }
       return !0;
     });
-    ed.setPendent = $.debounce(100, x => ed.dom.classList.toggle('pendent', x));
+    ed.setPendent = $.debounce(100, (x) => ed.dom.classList.toggle('pendent', x));
     ed.setTC(!!ed.tc);
     ed.setLN(D.prf.lineNums());
     ed.firstOpen = true;
@@ -154,8 +153,8 @@
       const ed = this;
       const model = ed.me.getModel();
       ed.stop = new Set(model.getAllDecorations()
-        .filter(d => d.options.glyphMarginClassName === 'breakpoint')
-        .map(d => d.range.startLineNumber - 1));
+        .filter((d) => d.options.glyphMarginClassName === 'breakpoint')
+        .map((d) => d.range.startLineNumber - 1));
     },
     cursorActivity(e) { // handle "cursor activity" event
       // xline:the line number of the empty line inserted when you press <down> at eof
@@ -202,7 +201,7 @@
     },
     setLN(x) { // update the display of line numbers and the state of the "[...]" button
       const ed = this;
-      ed.me.updateOptions({ lineNumbers: D.prf.lineNums() ? (l => `[${l - 1}]`) : 'off' });
+      ed.me.updateOptions({ lineNumbers: D.prf.lineNums() ? ((l) => `[${l - 1}]`) : 'off' });
       ed.dom.querySelector('.tb_LN').classList.toggle('pressed', !!x);
     },
     setTC(x) {
@@ -222,7 +221,7 @@
     },
     setStop() {
       const ed = this;
-      ed.stopDecorations = [...ed.stop].map(x => ({
+      ed.stopDecorations = [...ed.stop].map((x) => ({
         range: new monaco.Range(x + 1, 1, x + 1, 1),
         options: {
           isWholeLine: false,
@@ -247,7 +246,7 @@
     saveScrollPos() { },
     restoreScrollPos() { },
     updateSIStack(x) {
-      this.dom.querySelector('.si_stack').innerHTML = x.stack.map(o => `<option>${o}`).join('');
+      this.dom.querySelector('.si_stack').innerHTML = x.stack.map((o) => `<option>${o}`).join('');
     },
     stateChanged() {
       const w = this;
@@ -261,8 +260,8 @@
       ed.name = ee.name;
       // Check if a filename for a source file is provided.
       // Make sure it isn't duplicated in the existing name.
-      if (ee.filename && (ed.name.indexOf(ee.filename) == -1 )) {
-        ed.name = ed.name.concat(" in ", ee.filename)
+      if (ee.filename && (ed.name.indexOf(ee.filename) === -1)) {
+        ed.name = ed.name.concat(' in ', ee.filename);
       }
       ed.container && ed.container.setTitle(ed.name);
       D.ide.floating && $('title', ed.dom.ownerDocument).text(`${ed.name} - ${ed.ide.caption}`);
@@ -289,7 +288,8 @@
         me.setModel(monaco.editor.createModel(ed.oText, null, monaco.Uri.file(ee.name)));
       } else {
         monaco.editor.setModelLanguage(model, ed.isCode && !ed.isReadOnlyEntity ? 'apl' : 'plaintext');
-        etype && ed.dom.classList.toggle(etype, true);
+        ed.dom.classList.remove('charmat', 'chararr', 'numarr', 'mixarr', 'charvecvec', 'quador', 'charvec');
+        etype && ed.dom.classList.add(etype);
       }
       me.updateOptions({ folding: ed.isCode && !!D.prf.fold() });
       if (ed.isCode && D.prf.indentOnOpen()) ed.RD(me);
@@ -517,7 +517,7 @@
       const a = s.split(';');
       const head = a[0].replace(/\s+$/, '');
       let tail = a.length > 1 ? a.slice(1) : [];
-      tail = tail.map(x => x.replace(/\s+/g, ''));
+      tail = tail.map((x) => x.replace(/\s+/g, ''));
       const i = tail.indexOf(name); i < 0 ? tail.push(name) : tail.splice(i, 1);
       const text = [head].concat(tail.sort()).join(';') + (com || '');
       me.executeEdits('D', [{ range: new monaco.Range(l + 1, 1, l + 1, lt.length + 1), text }]);
@@ -544,13 +544,13 @@
           endLineNumber: q.lineNumber,
           endColumn: q.column,
         }, monaco.editor.EndOfLinePreference.LF).split('\n'); //  l:lines
-        const u = l.map(x => x.replace(/'[^']*'?/g, y => ' '.repeat(y.length))); // u:scrubbed strings
-        const c = u.map(x => x.indexOf('⍝')); // c:column index of ⍝
+        const u = l.map((x) => x.replace(/'[^']*'?/g, (y) => ' '.repeat(y.length))); // u:scrubbed strings
+        const c = u.map((x) => x.indexOf('⍝')); // c:column index of ⍝
         return {
           p, q, l, u, c,
         };
       });
-      const m = Math.max(...a.map(sel => Math.max(...sel.c)));
+      const m = Math.max(...a.map((sel) => Math.max(...sel.c)));
       const edits = a.map((sel) => {
         const r = sel.l.map((x, i) => {
           const ci = sel.c[i];
diff --git a/src/prf_col.js b/src/prf_col.js
index 08f1961b..431aa040 100644
--- a/src/prf_col.js
+++ b/src/prf_col.js
@@ -9,7 +9,31 @@
   let H = {}; // H:reverse lookup dict for G
   let M = {}; // H:reverse lookup dict for G
   let q; // dict of DOM elements whose ids start with "col_", keyed by the rest of the id
-  // D.addSynGrps(...) is the API for extensions, see ../sample-extensions/syntax-in-comments.js
+  let scms; // all schemes (built-in and user-defined) as objects
+  let scm = {}; //  the active scheme object
+  let me; //   Monaco editor instance for displaying sample code
+  let sel; //  the selected group's token type (.t)
+  // RGB() expands the hex representation of a colour, rgb() shrinks it
+  function RGB(x) {
+    const n = (x || '').length;
+    if (n === 6) return `#${x}`;
+    if (n === 3) return `#${x.replace(/(.)/g, '$1$1')}`;
+    return n === 1 ? `#${x.repeat(6)}` : x;
+  }
+  function RGBA(x, a) {
+    const r = RGB(x);
+    return `rgba(${[+`0x${r.slice(1, 3)}`, +`0x${r.slice(3, 5)}`, +`0x${r.slice(5, 7)}`, a]})`;
+  }
+  function RGBO(x, a) {
+    const o = a === undefined ? '' : `00${Math.round(a * 255).toString(16)}`.slice(-2);
+    return RGB(x) + o;
+  }
+  function rgb(x) {
+    if (!/^#.{6}$/.test(x)) return x;
+    const [, r, rr, g, gg, b, bb] = x;
+    if (r !== rr || g !== gg || b !== bb) return x.slice(1);
+    return r === g && g === b ? r : r + g + b;
+  }
   function encScm(x) {
     let s = '';
     Object.keys(x).forEach((g) => {
@@ -46,7 +70,7 @@
       }
     }
     if (!r.theme) { // check brightness and pick matching theme
-      const [rr, gg, bb] = RGB(r.norm.bg).match(/([0-9a-fA-F]{2})/g).map(c => parseInt(c, 16));
+      const [rr, gg, bb] = RGB(r.norm.bg).match(/([0-9a-fA-F]{2})/g).map((c) => parseInt(c, 16));
       const lum = Math.sqrt((0.241 * rr * rr) + (0.691 * gg * gg) + (0.068 * bb * bb));
       r.theme = lum < 130 ? 'dark' : 'light';
     }
@@ -131,43 +155,18 @@
   //     ...
   //   }
   // encScm() and decScm() convert between them
-  let scms; // all schemes (built-in and user-defined) as objects
-  let scm = {}; //  the active scheme object
-  let me; //   Monaco editor instance for displaying sample code
-  let sel; //  the selected group's token type (.t)
-  // RGB() expands the hex representation of a colour, rgb() shrinks it
-  function RGB(x) {
-    const n = (x || '').length;
-    if (n === 6) return `#${x}`;
-    if (n === 3) return `#${x.replace(/(.)/g, '$1$1')}`;
-    return n === 1 ? `#${x.repeat(6)}` : x;
-  }
-  function RGBA(x, a) {
-    const r = RGB(x);
-    return `rgba(${[+`0x${r.slice(1, 3)}`, +`0x${r.slice(3, 5)}`, +`0x${r.slice(5, 7)}`, a]})`;
-  }
-  function RGBO(x, a) {
-    const o = a === undefined ? '' : `00${Math.round(a * 255).toString(16)}`.slice(-2);
-    return RGB(x) + o;
-  }
-  function rgb(x) {
-    if (!/^#.{6}$/.test(x)) return x;
-    const [, r, rr, g, gg, b, bb] = x;
-    if (r !== rr || g !== gg || b !== bb) return x.slice(1);
-    return r === g && g === b ? r : r + g + b;
-  }
   function renderCSS(schema, isSample) {
     return G.map((g) => {
       const h = schema[g.t];
       if (!h || !g.c) return '';
-      const els = g.c.split(',').map(x => (isSample ? '#nonexistent' : x)).join(',');
+      const els = g.c.split(',').map((x) => (isSample ? '#nonexistent' : x)).join(',');
       const edmode = ['ca', 'cm', 'cv', 'cvv', 'ma', 'na', 'qor', 'dc'].includes(g.t);
       let cls;
       if (edmode) {
         cls = `${els} .monaco-editor-background,${els} .monaco-editor .margin{`;
         h.bg && (cls += `background-color:${RGB(h.bg)};`);
         h.bg && (cls += `background-color:${RGBA(h.bg, h.bgo == null ? 0.5 : h.bgo)};`);
-        cls += `}${els} .monaco-editor span{`;
+        cls += `}${els} .monaco-editor span,${els} .monaco-editor .line-numbers{`;
         h.fg && (cls += `color:${RGB(h.fg)};`);
         h.fg && (cls += `color:${RGBA(h.fg, h.fgo == null ? 1 : h.fgo)};`);
         h.B && (cls += 'font-weight:bold;');
@@ -220,7 +219,7 @@
         }
       }
     });
-    const name = `my${schema.name.split('').map(x => `${x.codePointAt(0)}`).join('')}`;
+    const name = `my${schema.name.split('').map((x) => `${x.codePointAt(0)}`).join('')}`;
     monaco.editor.defineTheme(name, {
       base: schema.theme === 'light' ? 'vs' : 'vs-dark',
       inherit: false,
@@ -386,7 +385,7 @@
         fg && u.indexOf(fg) < 0 && u.push(fg);
       });
       u.sort(); // u:unique colours
-      q.list.innerHTML = u.map(x => `<option value=${x}>`).join('');
+      q.list.innerHTML = u.map((x) => `<option value=${x}>`).join('');
       q.grp.innerHTML = G.map((g, i) => `<option value=${i}>${g.s}`).join('');
       q.scm.onchange = () => {
         scm = scms[+q.scm.selectedIndex];
@@ -447,7 +446,7 @@
         fontSize: fs,
         language: 'apl',
         lineHeight: fs + 2,
-        lineNumbers: x => `[${x - 1}]`,
+        lineNumbers: (x) => `[${x - 1}]`,
         minimap: { enabled: false },
         matchBrackets: true,
         mouseWheelZoom: false,
@@ -468,13 +467,15 @@
         + ':EndIf\n'
         + `${SC_MATCH}\n`,
       });
-      D.prf.blockCursor(x => me.updateOptions({ cursorStyle: x ? 'block' : 'line' }));
-      D.prf.cursorBlinking(x => me.updateOptions({ cursorBlinking: x }));
+      D.prf.blockCursor((x) => me.updateOptions({ cursorStyle: x ? 'block' : 'line' }));
+      D.prf.cursorBlinking((x) => me.updateOptions({ cursorBlinking: x }));
       let ss;
       function selGrpFromPosition(p) {
         const { lineNumber, column } = p;
         const s = ss[lineNumber - 1];
-        const si = s.tokens.map(x => x.startIndex).findIndex(x => x >= column - 1);
+        const si = s.tokens
+          .map((x) => x.startIndex)
+          .findIndex((x) => x >= column - 1);
         const t = s.tokens[si < 0 ? s.tokens.length - 1 : si - 1];
         let sc = t ? t.scopes.slice(0, -4) : '';
         while (!M[sc] && sc) sc = sc.slice(0, Math.max(0, sc.lastIndexOf('.')));
@@ -553,7 +554,7 @@
     },
     activate() { q.scm.focus(); },
     save() {
-      D.prf.colourSchemes(scms.filter(x => !x.frz).map(encScm));
+      D.prf.colourSchemes(scms.filter((x) => !x.frz).map(encScm));
       D.prf.colourScheme(scm.name);
     },
     resize() { },