From c1f41342119b608b9d8036ee48ea45bf455fbcce Mon Sep 17 00:00:00 2001
From: Matthias Melcher <github@matthiasm.com>
Date: Fri, 27 Dec 2024 21:16:35 -0500
Subject: [PATCH] Fluid: Improve UID generation.

---
 fluid/Fl_Type.cxx | 5 +++--
 fluid/file.cxx    | 2 ++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/fluid/Fl_Type.cxx b/fluid/Fl_Type.cxx
index 0f1026301f..49b0498f7b 100644
--- a/fluid/Fl_Type.cxx
+++ b/fluid/Fl_Type.cxx
@@ -703,8 +703,9 @@ void Fl_Type::add(Fl_Type *anchor, Strategy strategy) {
   }
 
 #ifdef FLUID_OPTION_MERGEBACK
+  if (   g_project.write_mergeback_data
+      && strategy.source() == Strategy::FROM_USER)
   { // make sure that we have no duplicate uid's
-    // FIXME: if 'add' is called while loading a file, the UID will be set by the tag later
     Fl_Type *tp = this;
     do {
       tp->set_uid(tp->uid_);
@@ -759,7 +760,7 @@ void Fl_Type::insert(Fl_Type *g) {
   g->prev = end;
   update_visibility_flag(this);
 #ifdef FLUID_OPTION_MERGEBACK
-  { // make sure that we have no duplicate uid's
+  if (g_project.write_mergeback_data) { // make sure that we have no duplicate uid's
     Fl_Type *tp = this;
     do {
       tp->set_uid(tp->uid_);
diff --git a/fluid/file.cxx b/fluid/file.cxx
index 9f5b78c391..4509a7a739 100644
--- a/fluid/file.cxx
+++ b/fluid/file.cxx
@@ -384,6 +384,8 @@ Fl_Type *Fd_Project_Reader::read_children(Fl_Type *p, int merge, Strategy strate
       if (!cc || !strcmp(cc,"}")) break;
       t->read_property(*this, cc);
     }
+    if (g_project.write_mergeback_data && t->get_uid()==0)
+      t->set_uid(0);
 
     if (t->can_have_children()) {
       c = read_word(1);