diff --git a/build/ImGui.linemap.json b/build/ImGui.linemap.json
index f3817bf..b5dd5c0 100644
--- a/build/ImGui.linemap.json
+++ b/build/ImGui.linemap.json
@@ -1 +1 @@
-[[13, "imgui.lua"], [12966, "imgui_demo.lua"], [13859, "imgui_demo_2.lua"], [16747, "imgui_docking.lua"], [19875, "imgui_dragdrop.lua"], [20167, "imgui_draw.lua"], [25162, "imgui_h.lua"], [27316, "imgui_impl_roblox.lua"], [28072, "imgui_impl_roblox_fonts.lua"], [28850, "imgui_internal.lua"], [31999, "imgui_tables.lua"], [32046, "imgui_tabs.lua"], [33213, "imgui_widgets.lua"], [41303, "imstb_rectpack.lua"], [41749, "imstb_textedit.lua"], [42990, "imstb_truetype.lua"], [45458, "imstd_minstdio.lua"]]
\ No newline at end of file
+[[12, "imgui.lua"], [12965, "imgui_demo.lua"], [13858, "imgui_demo_2.lua"], [16746, "imgui_docking.lua"], [19874, "imgui_dragdrop.lua"], [20166, "imgui_draw.lua"], [25161, "imgui_h.lua"], [27315, "imgui_impl_roblox.lua"], [28080, "imgui_impl_roblox_fonts.lua"], [28858, "imgui_internal.lua"], [32007, "imgui_tables.lua"], [32054, "imgui_tabs.lua"], [33221, "imgui_widgets.lua"], [41311, "imstb_rectpack.lua"], [41757, "imstb_textedit.lua"], [42998, "imstb_truetype.lua"], [45466, "imstd_minstdio.lua"]]
\ No newline at end of file
diff --git a/build/ImGui.luau b/build/ImGui.luau
index 87298bc..dd48162 100644
--- a/build/ImGui.luau
+++ b/build/ImGui.luau
@@ -1,4 +1,3 @@
---!native
 --!optimize 2
 -- GENERATED by tools/bundle.py from imgui/*.lua - do not edit
 
@@ -4458,7 +4457,7 @@ end
 local function GetWindowBgColorIdx(window)
     if bit32.band(window.Flags, bit32.bor(ImGuiWindowFlags.Tooltip, ImGuiWindowFlags.Popup)) ~= 0 then
         return ImGuiCol.PopupBg
-    elseif bit32.band(window.Flags, ImGuiWindowFlags.ChildWindow) ~= 0 then
+    elseif bit32.band(window.Flags, ImGuiWindowFlags.ChildWindow) ~= 0 and not window.DockIsActive then
         return ImGuiCol.ChildBg
     else
         return ImGuiCol.WindowBg
@@ -6058,9 +6057,9 @@ function ImGui.UpdateMouseMovingWindowNewFrame()
 
     if g.MovingWindow then
         ImGui.KeepAliveID(g.ActiveId)
-        IM_ASSERT(g.MovingWindow and g.MovingWindow.RootWindow)
+        IM_ASSERT(g.MovingWindow and g.MovingWindow.RootWindowDockTree)
 
-        local moving_window = g.MovingWindow.RootWindow
+        local moving_window = g.MovingWindow.RootWindowDockTree
 
         local window_disappeared = (not moving_window.WasActive and not moving_window.Active)
         if g.IO.MouseDown[0] and ImGui.IsMousePosValid(g.IO.MousePos) and not window_disappeared then
@@ -27512,6 +27511,7 @@ local TILE_SIZE -- Vector2, set below
 
 -- Blends one pixel (r, g, b, a are 0..255). One u32 read/write, one division in the general case.
 -- FillSpan below inlines the same math with per-span constants - keep the two in sync.
+@native
 local function BlendPixel(o, r, g, b, a)
     if a >= 255 then
         writeu32(buf, o, floor(r + 0.5) + floor(g + 0.5) * 256 + floor(b + 0.5) * 65536 + 4278190080)
@@ -27539,6 +27539,7 @@ local function BlendPixel(o, r, g, b, a)
 end
 
 -- Fills pixels [x0, x1) of row y with one colour
+@native
 local function FillSpan(y, x0, x1, r, g, b, a)
     if a <= 0 then return end
     local o0 = (y * buf_w + x0) * 4
@@ -27578,11 +27579,13 @@ local function FillSpan(y, x0, x1, r, g, b, a)
     end
 end
 
+@native
 local function UnpackColor(col)
     return col % 256, floor(col / 256) % 256, floor(col / 65536) % 256, floor(col / 16777216) % 256
 end
 
 -- Nearest texel at (u, v) as r, g, b, a (0..255)
+@native
 local function SampleTexture(t, u, v)
     local tw, th = t.Width, t.Height
     local tx, ty = floor(u * tw), floor(v * th)
@@ -27594,6 +27597,7 @@ local function SampleTexture(t, u, v)
 end
 
 -- Axis aligned, single colour quad (rects, glyphs, images). Pixel centers inside [x0, x1) x [y0, y1) are drawn.
+@native
 local function DrawRect(x0, y0, x1, y1, u0, v0, u1, v1, col, t, cx0, cy0, cx1, cy1)
     local r, g, b, a = UnpackColor(col)
     if a == 0 then return end
@@ -27651,6 +27655,7 @@ local function DrawRect(x0, y0, x1, y1, u0, v0, u1, v1, col, t, cx0, cy0, cx1, c
 end
 
 -- Generic triangle: per-vertex colour + uv, top-left fill rule, clipped to [cx0, cx1) x [cy0, cy1)
+@native
 local function DrawTriangle(va, vb, vc, t, cx0, cy0, cx1, cy1, ox, oy)
     local x0, y0 = va[1][1] - ox, va[1][2] - oy
     local x1, y1 = vb[1][1] - ox, vb[1][2] - oy
@@ -27727,6 +27732,7 @@ end
 
 -- Quads emitted by PrimRect/PrimRectUV/RenderText use indices (a, b, c, a, c, d) with a=TL, b=TR, c=BR, d=BL.
 -- When such a quad is axis aligned with one colour it is drawn with the much cheaper DrawRect.
+@native
 local function TryDrawRect(va, vb, vc, vd, t, cx0, cy0, cx1, cy1, ox, oy)
     local pa, pb, pc, pd = va[1], vb[1], vc[1], vd[1]
     if not (pa[2] == pb[2] and pb[1] == pc[1] and pc[2] == pd[2] and pd[1] == pa[1] and pa[1] < pb[1] and pa[2] < pd[2]) then return false end
@@ -27750,6 +27756,7 @@ local P1, P2 = 2147483647, 2147483629 -- two independent 31 bit hashes per tile
 local pr_a, pr_b, pr_c, pr_d, pr_t = {}, {}, {}, {}, {} -- vertices (pr_d == false -> triangle), texture
 local pr_cx0, pr_cy0, pr_cx1, pr_cy1 = {}, {}, {}, {}  -- clip (screen pixels)
 
+@native
 local function HashVertex(h1, h2, v)
     local p, u, c = v[1], v[2], v[3]
     local x, y = p[1], p[2]
@@ -27788,6 +27795,7 @@ local function DestroyTiles(bd)
     bd.Tiles = {}
 end
 
+@native
 function ImGui_ImplRoblox_RenderDrawData(draw_data)
     local bd = ImGui_ImplRoblox_GetBackendData()
 
diff --git a/imgui/backend/imgui_impl_roblox.lua b/imgui/backend/imgui_impl_roblox.lua
index 2bf5797..4a620b5 100644
--- a/imgui/backend/imgui_impl_roblox.lua
+++ b/imgui/backend/imgui_impl_roblox.lua
@@ -197,6 +197,7 @@ local TILE_SIZE -- Vector2, set below
 
 -- Blends one pixel (r, g, b, a are 0..255). One u32 read/write, one division in the general case.
 -- FillSpan below inlines the same math with per-span constants - keep the two in sync.
+@native
 local function BlendPixel(o, r, g, b, a)
     if a >= 255 then
         writeu32(buf, o, floor(r + 0.5) + floor(g + 0.5) * 256 + floor(b + 0.5) * 65536 + 4278190080)
@@ -224,6 +225,7 @@ local function BlendPixel(o, r, g, b, a)
 end
 
 -- Fills pixels [x0, x1) of row y with one colour
+@native
 local function FillSpan(y, x0, x1, r, g, b, a)
     if a <= 0 then return end
     local o0 = (y * buf_w + x0) * 4
@@ -263,11 +265,13 @@ local function FillSpan(y, x0, x1, r, g, b, a)
     end
 end
 
+@native
 local function UnpackColor(col)
     return col % 256, floor(col / 256) % 256, floor(col / 65536) % 256, floor(col / 16777216) % 256
 end
 
 -- Nearest texel at (u, v) as r, g, b, a (0..255)
+@native
 local function SampleTexture(t, u, v)
     local tw, th = t.Width, t.Height
     local tx, ty = floor(u * tw), floor(v * th)
@@ -279,6 +283,7 @@ local function SampleTexture(t, u, v)
 end
 
 -- Axis aligned, single colour quad (rects, glyphs, images). Pixel centers inside [x0, x1) x [y0, y1) are drawn.
+@native
 local function DrawRect(x0, y0, x1, y1, u0, v0, u1, v1, col, t, cx0, cy0, cx1, cy1)
     local r, g, b, a = UnpackColor(col)
     if a == 0 then return end
@@ -336,6 +341,7 @@ local function DrawRect(x0, y0, x1, y1, u0, v0, u1, v1, col, t, cx0, cy0, cx1, c
 end
 
 -- Generic triangle: per-vertex colour + uv, top-left fill rule, clipped to [cx0, cx1) x [cy0, cy1)
+@native
 local function DrawTriangle(va, vb, vc, t, cx0, cy0, cx1, cy1, ox, oy)
     local x0, y0 = va[1][1] - ox, va[1][2] - oy
     local x1, y1 = vb[1][1] - ox, vb[1][2] - oy
@@ -412,6 +418,7 @@ end
 
 -- Quads emitted by PrimRect/PrimRectUV/RenderText use indices (a, b, c, a, c, d) with a=TL, b=TR, c=BR, d=BL.
 -- When such a quad is axis aligned with one colour it is drawn with the much cheaper DrawRect.
+@native
 local function TryDrawRect(va, vb, vc, vd, t, cx0, cy0, cx1, cy1, ox, oy)
     local pa, pb, pc, pd = va[1], vb[1], vc[1], vd[1]
     if not (pa[2] == pb[2] and pb[1] == pc[1] and pc[2] == pd[2] and pd[1] == pa[1] and pa[1] < pb[1] and pa[2] < pd[2]) then return false end
@@ -435,6 +442,7 @@ local P1, P2 = 2147483647, 2147483629 -- two independent 31 bit hashes per tile
 local pr_a, pr_b, pr_c, pr_d, pr_t = {}, {}, {}, {}, {} -- vertices (pr_d == false -> triangle), texture
 local pr_cx0, pr_cy0, pr_cx1, pr_cy1 = {}, {}, {}, {}  -- clip (screen pixels)
 
+@native
 local function HashVertex(h1, h2, v)
     local p, u, c = v[1], v[2], v[3]
     local x, y = p[1], p[2]
@@ -473,6 +481,7 @@ local function DestroyTiles(bd)
     bd.Tiles = {}
 end
 
+@native
 function ImGui_ImplRoblox_RenderDrawData(draw_data)
     local bd = ImGui_ImplRoblox_GetBackendData()
 
diff --git a/imgui/imgui.lua b/imgui/imgui.lua
index 20d8517..40bd53e 100644
--- a/imgui/imgui.lua
+++ b/imgui/imgui.lua
@@ -4446,7 +4446,7 @@ end
 local function GetWindowBgColorIdx(window)
     if bit32.band(window.Flags, bit32.bor(ImGuiWindowFlags.Tooltip, ImGuiWindowFlags.Popup)) ~= 0 then
         return ImGuiCol.PopupBg
-    elseif bit32.band(window.Flags, ImGuiWindowFlags.ChildWindow) ~= 0 then
+    elseif bit32.band(window.Flags, ImGuiWindowFlags.ChildWindow) ~= 0 and not window.DockIsActive then
         return ImGuiCol.ChildBg
     else
         return ImGuiCol.WindowBg
@@ -6046,9 +6046,9 @@ function ImGui.UpdateMouseMovingWindowNewFrame()
 
     if g.MovingWindow then
         ImGui.KeepAliveID(g.ActiveId)
-        IM_ASSERT(g.MovingWindow and g.MovingWindow.RootWindow)
+        IM_ASSERT(g.MovingWindow and g.MovingWindow.RootWindowDockTree)
 
-        local moving_window = g.MovingWindow.RootWindow
+        local moving_window = g.MovingWindow.RootWindowDockTree
 
         local window_disappeared = (not moving_window.WasActive and not moving_window.Active)
         if g.IO.MouseDown[0] and ImGui.IsMousePosValid(g.IO.MousePos) and not window_disappeared then
diff --git a/tools/bundle.py b/tools/bundle.py
index f25f015..8be59e7 100644
--- a/tools/bundle.py
+++ b/tools/bundle.py
@@ -20,7 +20,7 @@ for src in FILES.values():
     names.update(re.findall(r"^function ([A-Za-z_]\w*)\s*\(", src, re.M))
     names.update(re.findall(r"^([A-Za-z_]\w*)\s*=[^=]", src, re.M))
 
-out = ["--!native", "--!optimize 2", "-- GENERATED by tools/bundle.py from imgui/*.lua - do not edit", "",
+out = ["--!optimize 2", "-- GENERATED by tools/bundle.py from imgui/*.lua - do not edit", "",
        "local __FILES, __LOADED = {}, {}",
        "function IM_INCLUDE(name)",
        "    local r = __LOADED[name]",
diff --git a/tools/test/scripts/t_dock_move.luau b/tools/test/scripts/t_dock_move.luau
new file mode 100644
index 0000000..0347a9f
--- /dev/null
+++ b/tools/test/scripts/t_dock_move.luau
@@ -0,0 +1,59 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local RunService = game:GetService("RunService")
+local G = require(ReplicatedStorage:WaitForChild("ImGui"))
+local ImGui, ImVec2 = G.ImGui, G.ImVec2
+ImGui.CreateContext()
+local io = ImGui.GetIO()
+io.ConfigFlags = bit32.bor(io.ConfigFlags, G.ImGuiConfigFlags.DockingEnable)
+G.ImGui_ImplRoblox.Init()
+local frame, last_down, host0 = 0, false, nil
+local function lerp(a, b, t) return a + (b - a) * t end
+local function script(f)
+    if f < 6 then return 600, 108, false end
+    if f == 6 then return 600, 108, true end
+    if f <= 20 then local t = (f - 6) / 14 return lerp(600, 250, t), lerp(108, 190, t), true end
+    if f <= 27 then return 250, 190, true end
+    if f <= 40 then return 250, 190, false end
+    -- now grab empty space of the shared tab bar (right of the tabs) and move
+    if f == 41 then return 380, 108, false end
+    if f == 42 then return 380, 108, true end
+    if f <= 56 then local t = (f - 42) / 14 return lerp(380, 600, t), lerp(108, 300, t), true end
+    return 600, 300, false
+end
+RunService.Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    local x, y, down = script(frame)
+    io:AddMousePosEvent(x, y)
+    if down ~= last_down then io:AddMouseButtonEvent(0, down); last_down = down end
+    ImGui.NewFrame()
+    for i, n in ipairs({"A", "B"}) do
+        ImGui.SetNextWindowPos(ImVec2(100 + (i - 1) * 400, 100), G.ImGuiCond.FirstUseEver)
+        ImGui.SetNextWindowSize(ImVec2(300, 200), G.ImGuiCond.FirstUseEver)
+        if ImGui.Begin(n) then ImGui.Text("window " .. n) end
+        ImGui.End()
+    end
+    local a = ImGui.FindWindowByName("A")
+    if frame == 40 then
+        assert(a.DockNode and a.DockNode.Windows.Size == 2, "docked")
+        host0 = {Pos = {x = a.DockNode.HostWindow.Pos.x, y = a.DockNode.HostWindow.Pos.y}}
+        print("host before", host0.Pos.x, host0.Pos.y)
+    end
+    if frame == 70 then
+        local h = a.DockNode.HostWindow
+        print("host after", h.Pos.x, h.Pos.y)
+        assert(math.abs(h.Pos.x - host0.Pos.x) > 100 or math.abs(h.Pos.y - host0.Pos.y) > 50, "dock host must move")
+        -- background: host draw list must contain a filled rect covering the node body
+    end
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+    if frame == 70 then
+        local want = ImGui.GetColorU32(G.ImGuiCol.WindowBg)
+        local found = false
+        for _, l in ImGui.GetDrawData().CmdLists:iter() do
+            for i = 1, l.VtxBuffer.Size do if l.VtxBuffer.Data[i][3] == want then found = true break end end
+        end
+        assert(found, "docked windows must draw a WindowBg background")
+        print("MOVE OK")
+    end
+end)