diff --git a/src/Lean/Server/FileWorker.lean b/src/Lean/Server/FileWorker.lean
index a8582ccdf3f9..c57479690214 100644
--- a/src/Lean/Server/FileWorker.lean
+++ b/src/Lean/Server/FileWorker.lean
@@ -51,17 +51,7 @@ open IO
 open Snapshots
 open Std (RBMap RBMap.empty)
 open JsonRpc
-
-def publishInteractiveMessages (m : DocumentMeta) (msgLog : MessageLog) (hOut : FS.Stream) (rpcSesh : RpcSession) : IO Unit := do
-  let diagnostics ← msgLog.msgs.mapM (Widget.msgToDiagnostic m.text · rpcSesh)
-  let diagParams : PublishDiagnosticsParams :=
-    { uri := m.uri
-      version? := some m.version
-      diagnostics := diagnostics.toArray }
-  hOut.writeLspNotification {
-    method := "textDocument/publishDiagnostics"
-    param := toJson diagParams
-  }
+open Widget (publishMessages)
 
 /- Asynchronous snapshot elaboration. -/
 section Elab
@@ -85,10 +75,10 @@ section Elab
         because we cannot guarantee that no further diagnostics are emitted after clearing
         them. -/
       if snap.msgLog.msgs.size > parentSnap.msgLog.msgs.size then
-        publishInteractiveMessages m snap.msgLog hOut rpcSesh
+        publishMessages m snap.msgLog hOut rpcSesh
       snap
     | Sum.inr msgLog =>
-      publishInteractiveMessages m msgLog hOut rpcSesh
+      publishMessages m msgLog hOut rpcSesh
       publishProgressDone m hOut
       throw ElabTaskError.eof
 
@@ -160,7 +150,7 @@ section Initialization
     else
       throwServerError s!"`leanpkg print-paths` failed:\n{stdout}\nstderr:\n{stderr}"
 
-  def compileHeader (m : DocumentMeta) (hOut : FS.Stream) : IO (Snapshot × SearchPath) := do
+  def compileHeader (m : DocumentMeta) (hOut : FS.Stream) (rpcSesh : RpcSession) : IO (Snapshot × SearchPath) := do
     let opts := {}  -- TODO
     let inputCtx := Parser.mkInputContext m.text.source "<input>"
     let (headerStx, headerParserState, msgLog) ← Parser.parseHeader inputCtx
@@ -180,7 +170,7 @@ section Initialization
     catch e =>  -- should be from `leanpkg print-paths`
       let msgs := MessageLog.empty.add { fileName := "<ignored>", pos := ⟨0, 0⟩, data := e.toString }
       pure (← mkEmptyEnvironment, msgs)
-    --publishMessages m msgLog hOut
+    publishMessages m msgLog hOut rpcSesh
     let cmdState := Elab.Command.mkState headerEnv msgLog opts
     let cmdState := { cmdState with infoState.enabled := true, scopes := [{ header := "", opts := opts }] }
     let headerSnap := {
@@ -193,14 +183,9 @@ section Initialization
 
   def initializeWorker (meta : DocumentMeta) (i o e : FS.Stream)
       : IO (WorkerContext × WorkerState) := do
-    /- NOTE(WN): `toFileMap` marks line beginnings as immediately following
-      "\n", which should be enough to handle both LF and CRLF correctly.
-      This is because LSP always refers to characters by (line, column),
-      so if we get the line number correct it shouldn't matter that there
-      is a CR there. -/
-    let (headerSnap, srcSearchPath) ← compileHeader meta o
-    let cancelTk ← CancelToken.new
     let rpcSesh ← RpcSession.new false
+    let (headerSnap, srcSearchPath) ← compileHeader meta o rpcSesh
+    let cancelTk ← CancelToken.new
     let cmdSnaps ← unfoldCmdSnaps meta headerSnap cancelTk o (initial := true) rpcSesh
     let doc : EditableDocument := ⟨meta, headerSnap, cmdSnaps, cancelTk⟩
     return ({
@@ -392,6 +377,11 @@ def initAndRunWorker (i o e : FS.Stream) : IO UInt32 := do
   let _ ← i.readLspRequestAs "initialize" InitializeParams
   let ⟨_, param⟩ ← i.readLspNotificationAs "textDocument/didOpen" DidOpenTextDocumentParams
   let doc := param.textDocument
+  /- NOTE(WN): `toFileMap` marks line beginnings as immediately following
+    "\n", which should be enough to handle both LF and CRLF correctly.
+    This is because LSP always refers to characters by (line, column),
+    so if we get the line number correct it shouldn't matter that there
+    is a CR there. -/
   let meta : DocumentMeta := ⟨doc.uri, doc.version, doc.text.toFileMap⟩
   let e ← e.withPrefix s!"[{param.textDocument.uri}] "
   let _ ← IO.setStderr e
diff --git a/src/Lean/Widget.lean b/src/Lean/Widget.lean
index 146de08bf09e..54db7242a6f4 100644
--- a/src/Lean/Widget.lean
+++ b/src/Lean/Widget.lean
@@ -8,4 +8,3 @@ import Lean.Widget.ExprWithCtx
 import Lean.Widget.InteractiveGoals
 import Lean.Widget.InteractiveDiagnostics
 import Lean.Widget.TaggedText
-import Lean.Widget.ToHtmlFormat
diff --git a/src/Lean/Widget/InteractiveDiagnostics.lean b/src/Lean/Widget/InteractiveDiagnostics.lean
index b32a1038bedd..e2ec56a1619c 100644
--- a/src/Lean/Widget/InteractiveDiagnostics.lean
+++ b/src/Lean/Widget/InteractiveDiagnostics.lean
@@ -1,3 +1,9 @@
+/-
+Copyright (c) 2021 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Authors: Wojciech Nawrocki
+-/
 import Lean.Data.Lsp
 import Lean.Message
 import Lean.Server.Rpc.Basic
@@ -111,4 +117,15 @@ def msgToDiagnostic (text : FileMap) (m : Message) : ReaderT RpcSession IO Diagn
     taggedMsg? := ttJson
   }
 
+def publishMessages (m : DocumentMeta) (msgLog : MessageLog) (hOut : IO.FS.Stream) (rpcSesh : RpcSession) : IO Unit := do
+  let diagnostics ← msgLog.msgs.mapM (msgToDiagnostic m.text · rpcSesh)
+  let diagParams : PublishDiagnosticsParams :=
+    { uri := m.uri
+      version? := some m.version
+      diagnostics := diagnostics.toArray }
+  hOut.writeLspNotification {
+    method := "textDocument/publishDiagnostics"
+    param := toJson diagParams
+  }
+
 end Lean.Widget
diff --git a/src/Lean/Widget/TaggedText.lean b/src/Lean/Widget/TaggedText.lean
index 22267a97ca6a..fd3ba7ad419d 100644
--- a/src/Lean/Widget/TaggedText.lean
+++ b/src/Lean/Widget/TaggedText.lean
@@ -65,11 +65,6 @@ def appendTag (acc : TaggedText α) (t₀ : α) (a₀ : TaggedText α) : TaggedT
   | append as => append (as.push <| tag t₀ a₀)
   | a         => append #[a, tag t₀ a₀]
 
-partial def toString [ToString α] : TaggedText α → String
-  | text s => s
-  | append as => " ++ ".intercalate (as.toList.map toString)
-  | tag t a => s!"([{t}] {toString a})"
-
 partial def map (f : α → β) : TaggedText α → TaggedText β :=
   go
 where go : TaggedText α → TaggedText β
diff --git a/src/Lean/Widget/ToHtmlFormat.lean b/src/Lean/Widget/ToHtmlFormat.lean
deleted file mode 100644
index 521b3dfedf91..000000000000
--- a/src/Lean/Widget/ToHtmlFormat.lean
+++ /dev/null
@@ -1,6 +0,0 @@
-/-- Types implementing this can displayed in HTML, for example as a SVG.
-This is non-interactive -- for interactivity, see widgets. -/
--- should suffice for Dynkin
--- https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/Dynkin.20diagrams
-class ToHtmlFormat (α : Type u) where
-  toHtmlFormat : α → String -- TODO HTML