diff --git a/extern/imgui_patched/imgui_widgets.cpp b/extern/imgui_patched/imgui_widgets.cpp
index 93dfd534..d6ddfdb8 100644
--- a/extern/imgui_patched/imgui_widgets.cpp
+++ b/extern/imgui_patched/imgui_widgets.cpp
@@ -3713,7 +3713,12 @@ static bool STB_TEXTEDIT_INSERTCHARS(ImGuiInputTextState* obj, int pos, const Im
 {
     const bool is_resizable = (obj->Flags & ImGuiInputTextFlags_CallbackResize) != 0;
     const int text_len = obj->CurLenW;
-    IM_ASSERT(pos <= text_len);
+    if (pos > text_len) {
+      printf("failing STB_TEXTEDIT_INSERTCHARS assertion! oh man...\n");
+      obj->Edited = true; // ???
+      obj->ClearText();
+      return false;
+    }
 
     const int new_text_len_utf8 = ImTextCountUtf8BytesFromStr(new_text, new_text + new_text_len);
     if (!is_resizable && (new_text_len_utf8 + obj->CurLenA + 1 > obj->BufCapacityA))
@@ -3776,8 +3781,11 @@ static void stb_textedit_replace(ImGuiInputTextState* str, STB_TexteditState* st
         state->cursor = text_len;
         state->has_preferred_x = 0;
         return;
+    } else {
+      state->cursor = 0;
+      printf("STB_TEXTEDIT_INSERTCHARS fail!\n");
     }
-    IM_ASSERT(0); // Failed to insert character, normally shouldn't happen because of how we currently use stb_textedit_replace()
+    //IM_ASSERT(0); // Failed to insert character, normally shouldn't happen because of how we currently use stb_textedit_replace()
 }
 
 } // namespace ImStb
@@ -3962,7 +3970,8 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
     const bool is_multiline = (flags & ImGuiInputTextFlags_Multiline) != 0;
     const bool is_readonly = (flags & ImGuiInputTextFlags_ReadOnly) != 0;
     const bool is_password = (flags & ImGuiInputTextFlags_Password) != 0;
-    const bool is_undoable = (flags & ImGuiInputTextFlags_NoUndoRedo) == 0;
+    // https://github.com/tildearrow/furnace/issues/624
+    const bool is_undoable = 0; //(flags & ImGuiInputTextFlags_NoUndoRedo) == 0;
     const bool is_resizable = (flags & ImGuiInputTextFlags_CallbackResize) != 0;
     if (is_resizable)
         IM_ASSERT(callback != NULL); // Must provide a callback if you set the ImGuiInputTextFlags_CallbackResize flag!
diff --git a/extern/imgui_patched/imstb_textedit.h b/extern/imgui_patched/imstb_textedit.h
index 75a159da..d9364230 100644
--- a/extern/imgui_patched/imstb_textedit.h
+++ b/extern/imgui_patched/imstb_textedit.h
@@ -717,6 +717,9 @@ static int stb_textedit_paste_internal(STB_TEXTEDIT_STRING *str, STB_TexteditSta
       state->cursor += len;
       state->has_preferred_x = 0;
       return 1;
+   } else {
+     printf("stb_textedit_paste_internal failed.\n");
+     state->cursor=0;
    }
    // note: paste failure will leave deleted selection, may be restored with an undo (see https://github.com/nothings/stb/issues/734 for details)
    return 0;
@@ -746,6 +749,9 @@ retry:
                if (STB_TEXTEDIT_INSERTCHARS(str, state->cursor, &ch, 1)) {
                   ++state->cursor;
                   state->has_preferred_x = 0;
+               } else {
+                 printf("key failed: first section.\n");
+                 state->cursor=0;
                }
             } else {
                stb_textedit_delete_selection(str,state); // implicitly clamps
@@ -753,6 +759,9 @@ retry:
                   stb_text_makeundo_insert(state, state->cursor, 1);
                   ++state->cursor;
                   state->has_preferred_x = 0;
+               } else {
+                 printf("key failed: second section.\n");
+                 state->cursor=0;
                }
             }
          }
@@ -1275,14 +1284,22 @@ static void stb_text_undo(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
       STB_TEXTEDIT_DELETECHARS(str, u.where, u.delete_length);
    }
 
+   bool steFailed=false;
+
    // check type of recorded action:
    if (u.insert_length) {
       // easy case: was a deletion, so we need to insert n characters
-      STB_TEXTEDIT_INSERTCHARS(str, u.where, &s->undo_char[u.char_storage], u.insert_length);
+      if (!STB_TEXTEDIT_INSERTCHARS(str, u.where, &s->undo_char[u.char_storage], u.insert_length)) {
+        printf("undo u.insert_length failed\n");
+        state->cursor=0;
+        steFailed=true;
+      }
       s->undo_char_point -= u.insert_length;
    }
 
-   state->cursor = u.where + u.insert_length;
+   if (!steFailed) {
+     state->cursor = u.where + u.insert_length;
+   }
 
    s->undo_point--;
    s->redo_point--;
@@ -1327,13 +1344,21 @@ static void stb_text_redo(STB_TEXTEDIT_STRING *str, STB_TexteditState *state)
       STB_TEXTEDIT_DELETECHARS(str, r.where, r.delete_length);
    }
 
+   bool steFailed=false;
+
    if (r.insert_length) {
       // easy case: need to insert n characters
-      STB_TEXTEDIT_INSERTCHARS(str, r.where, &s->undo_char[r.char_storage], r.insert_length);
+      if (!STB_TEXTEDIT_INSERTCHARS(str, r.where, &s->undo_char[r.char_storage], r.insert_length)) {
+        printf("redo insert char failed\n");
+        state->cursor=0;
+        steFailed=true;
+      }
       s->redo_char_point += r.insert_length;
    }
 
-   state->cursor = r.where + r.insert_length;
+   if (!steFailed) {
+     state->cursor = r.where + r.insert_length;
+   }
 
    s->undo_point++;
    s->redo_point++;