diff --git a/src/net/torvald/terrarum/modulebasegame/ui/UIBuildingMakerBlockChooser.kt b/src/net/torvald/terrarum/modulebasegame/ui/UIBuildingMakerBlockChooser.kt
index b32ccb460..aa12a4067 100644
--- a/src/net/torvald/terrarum/modulebasegame/ui/UIBuildingMakerBlockChooser.kt
+++ b/src/net/torvald/terrarum/modulebasegame/ui/UIBuildingMakerBlockChooser.kt
@@ -18,7 +18,7 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
 
     companion object {
         const val TILES_X = 8
-        const val TILES_Y = 8
+        const val TILES_Y = 10
 
         const val TILESREGION_SIZE = 24
         const val MENUBAR_SIZE = 72
@@ -37,7 +37,7 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
     // TODO scrolling of the palette, as the old method flat out won't work with The Flattening
 
     private val tabs = UIItemTextButtonList(
-        this, 36, arrayOf("Terrain", "Wall", "Wire"),
+        this, 36, arrayOf("Terrain", "Wall", "Wire"), // TODO use inventory icons
         0, 0, textAreaWidth = MENUBAR_SIZE, width = MENUBAR_SIZE,
         defaultSelection = 0,
         backgroundCol = UIItemTextButtonList.DEFAULT_BACKGROUNDCOL
@@ -49,6 +49,14 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
         backgroundCol = UIItemTextButtonList.DEFAULT_BACKGROUNDCOL
     )
 
+    private var scroll = 0
+
+    private val <E> List<E>.visible: List<E>
+        get()  = this.subList(
+            TILES_X * scroll,
+            (TILES_X * scroll + TILES_X * TILES_Y).coerceAtMost(this.size)
+        )
+
     init {
 
         BlockCodex.getAll().filter {
@@ -58,7 +66,7 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
             catch (e: NullPointerException) {
                 null
             }) != null
-        }.filter { !it.hasTag("INTERNAL") }.sortedBy { it.id }.forEachIndexed { index, prop ->
+        }.filter { !it.hasTag("INTERNAL") }.sortedBy { it.id }.forEachIndexed { index, prop -> // FIXME no lexicographic sorting
             val paletteItem = UIItemImageButton(
                 this, ItemCodex.getItemImage(prop.id)!!,
                 initialX = MENUBAR_SIZE + (index % TILES_X) * TILESREGION_SIZE,
@@ -67,14 +75,14 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
                 width = TILESREGION_SIZE,
                 height = TILESREGION_SIZE,
                 highlightCol = Color.WHITE,
-                activeCol = Color.WHITE
+                activeCol = Color.WHITE,
+                backgroundCol = Color(0)
             )
 
             paletteItem.clickOnceListener = { _, _ ->
                 parent.setPencilColour(prop.id)
             }
 
-            uiItems.add(paletteItem)
             palette.add(paletteItem)
         }
     }
@@ -82,13 +90,13 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
     private val scrollOverflowSize = ((palette.size - TILES_X * TILES_Y).toDouble() / TILES_X).ceilToDouble().coerceAtLeast(0.0)
 
     private val scrollBar = UIItemVertSlider(
-        this, WIDTH - UIItemVertSlider.WIDTH, 0, 0.0, 0.0, scrollOverflowSize, height, SCROLLBAR_SIZE
+        this, WIDTH - UIItemVertSlider.WIDTH, 0, 0.0, 0.0, scrollOverflowSize, height, (height * TILES_Y / (scrollOverflowSize + TILES_Y)).ceilToInt()
     ).also {
         println("scrollOverflowSize = $scrollOverflowSize")
 
         addUIitem(it)
-        it.scrolledListener = { scrollX, scrollY ->
-
+        it.selectionChangeListener = { value ->
+            scroll = value.roundToInt()
         }
     }
 
@@ -102,6 +110,10 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
             closeGracefully()
         }
 
+        palette.visible.forEach {
+            it.update(delta)
+        }
+
         uiItems.forEach { it.update(delta) }
     }
 
@@ -117,6 +129,10 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
     override fun renderUI(batch: SpriteBatch, camera: OrthographicCamera) {
         blendNormalStraightAlpha(batch)
 
+        // border
+        batch.color = Toolkit.Theme.COL_INACTIVE
+        Toolkit.drawBoxBorder(batch, -1, -1, width + 2, height + 2)
+
         // background
         batch.color = DEFAULT_BACKGROUNDCOL
         Toolkit.fillArea(batch, 0, 0, width, height)
@@ -129,6 +145,10 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
         tabs.render(batch, camera)
         closeButton.render(batch, camera)
 
+        palette.visible.forEach {
+            it.render(batch, camera, 0, -scroll * TILESREGION_SIZE)
+        }
+
         uiItems.forEach { it.render(batch, camera) }
     }
 
@@ -162,6 +182,10 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
             dragForReal = false
         }
 
+        palette.visible.forEach {
+            it.touchDown(screenX, screenY, pointer, button)
+        }
+
         return super.touchDown(screenX, screenY, pointer, button)
     }
 
@@ -169,6 +193,12 @@ class UIBuildingMakerBlockChooser(val parent: BuildingMaker): UICanvas() {
         return super.touchUp(screenX, screenY, pointer, button)
     }
 
+    override fun scrolled(amountX: Float, amountY: Float): Boolean {
+        scrollBar.scrolledForce(amountX, amountY)
+
+        return super.scrolled(amountX, amountY)
+    }
+
     override fun doOpening(delta: Float) {
     }
 
diff --git a/src/net/torvald/terrarum/ui/UIItemImageButton.kt b/src/net/torvald/terrarum/ui/UIItemImageButton.kt
index 091ae0f47..6adb6a23a 100644
--- a/src/net/torvald/terrarum/ui/UIItemImageButton.kt
+++ b/src/net/torvald/terrarum/ui/UIItemImageButton.kt
@@ -54,7 +54,10 @@ open class UIItemImageButton(
     var highlighted = false
     var extraDrawOp: (UIItem, SpriteBatch) -> Unit = { _,_ -> }
 
-    override fun render(batch: SpriteBatch, camera: OrthographicCamera) {
+    fun render(batch: SpriteBatch, camera: OrthographicCamera, offX: Int, offY: Int) {
+        val posX = this.posX + offX
+        val posY = this.posY + offY
+
         // draw background
         if (highlighted) {
             BlendMode.resolve(highlightBackBlendMode, batch)
@@ -90,6 +93,10 @@ open class UIItemImageButton(
         extraDrawOp(this, batch)
     }
 
+    override fun render(batch: SpriteBatch, camera: OrthographicCamera) {
+        render(batch, camera, 0, 0)
+    }
+
     override fun dispose() {
         image.texture.dispose()
     }
diff --git a/src/net/torvald/terrarum/ui/UIItemVertSlider.kt b/src/net/torvald/terrarum/ui/UIItemVertSlider.kt
index c2ba8cea8..a2a22dae6 100644
--- a/src/net/torvald/terrarum/ui/UIItemVertSlider.kt
+++ b/src/net/torvald/terrarum/ui/UIItemVertSlider.kt
@@ -31,7 +31,7 @@ class UIItemVertSlider(
     private var mouseOnHandle = false
 
     private val handleTravelDist = height - handleHeight
-    private var handlePos = (initialValue / max).times(handleTravelDist).coerceIn(0.0, handleTravelDist.toDouble())
+    private var handlePos = if (max == 0.0) 0.0 else (initialValue / max).times(handleTravelDist).coerceIn(0.0, handleTravelDist.toDouble())
 
     var value: Double = initialValue; private set
     var selectionChangeListener: (Double) -> Unit = {}