use docking branch

.gitmodules

@@ -12,6 +12,7 @@
 [submodule "extern/imgui"]
 	path = extern/imgui
 	url = https://github.com/ocornut/imgui.git
+	branch = docking
 [submodule "extern/fmt"]
 	path = extern/fmt
 	url = https://github.com/fmtlib/fmt.git

extern/imgui

@@ -1 +1 @@
-Subproject commit 8a9fe268662292ed9495048d942d8d0341c03185
+Subproject commit 747f7fdbbaa1fdd46d5115c7333ab0722a7c2afc

src/gui/gui.cpp

@@ -689,6 +689,8 @@ bool FurnaceGUI::init() {
 
   sty.ScaleAllSizes(dpiScale);
 
+  ImGui::GetIO().ConfigFlags|=ImGuiConfigFlags_DockingEnable;
+
   if ((mainFont=ImGui::GetIO().Fonts->AddFontFromMemoryCompressedTTF(defFont_main_compressed_data,defFont_main_compressed_size,18*dpiScale))==NULL) {
     logE("could not load UI font!\n");
     return false;