fix: guard drop-zone clamp bounds for tiny drag targets

Normalize drop-zone clamp ranges before calling Math.clamp so tiny leaf bounds cannot trigger IllegalArgumentException during drag hover.

Add a DockLayoutEngine regression test for tiny bounds to ensure zone generation stays stable and does not throw in addElementZones.

Update STATUS/DONE/ROADMAP/CHANGELOG to reflect the fix and 189 passing tests.

Author: Beowolve

CHANGELOG.md

@@ -10,7 +10,7 @@ The changelog is grouped by release tags (`vX.Y.Z`) and includes an `Unreleased`
 - ✅ Removed obsolete JavaFX test JVM module flags that caused classpath/module warning noise (`24ac0bc`).
 - ✅ Stabilized JavaFX module-path test runtime without FXML assumptions (`e8197a9`).
 - ✅ Migrated plugin/dependency versions to `gradle/libs.versions.toml` and reduced duplicated build configuration (`517b5db`).
-- ✅ Expanded shortcut, context-menu, and demo-accelerator coverage in unit tests; full suite now runs with 188 tests.
+- ✅ Expanded shortcut, context-menu, and demo-accelerator coverage in unit tests; full suite now runs with 189 tests.
 
 ### Framework and UI
 - ✅ Added configurable framework keyboard shortcut API in `SnapFX` (`setShortcut`, `clearShortcut`, `resetShortcutsToDefaults`, `getShortcuts`).
@@ -23,6 +23,7 @@ The changelog is grouped by release tags (`vX.Y.Z`) and includes an `Unreleased`
 - ✅ Added close/float control-glyph icons to dock-node and tab context-menu actions for visual parity with header/tab buttons.
 - ✅ Reworked DockNode icon model to image-based rendering so each view creates its own icon node, preventing parent-sharing losses in floating title bars.
 - ✅ Floating title-bar icon now tracks active tab selection in floating tab layouts.
+- ✅ Hardened drop-zone edge-size clamping for tiny bounds so drag hover no longer throws `Math.clamp` min/max-order exceptions.
 
 ### Documentation
 - ✅ Split repository workflow content out of `README.md` into dedicated `CONTRIBUTING.md` and `RELEASING.md` (`6f93d0a`).

DONE.md

@@ -59,7 +59,7 @@ SnapFX has been fully implemented with core functionality and is production-read
 - ✅ Full JPMS support with proper exports and opens
 - ✅ Compatible with Java 21 module system
 
-### Testing (12 test classes, 188 tests)
+### Testing (12 test classes, 189 tests)
 - ✅ `DockGraphTest` (56 tests) - Tree manipulation and algorithms
   - **+11 regression tests** for critical bug fixes
   - Tests for empty container prevention
@@ -70,7 +70,7 @@ SnapFX has been fully implemented with core functionality and is production-read
   - Edge case tests for null/no-op/detached-target handling
 - ✅ `DockLayoutSerializerTest` (9 tests) - Persistence functionality
   - **+1 regression test** for locked state synchronization (2026-02-10)
-- ✅ `DockLayoutEngineTest` (28 tests) - View creation with TestFX, context-menu interaction coverage, and float-availability policy checks
+- ✅ `DockLayoutEngineTest` (29 tests) - View creation with TestFX, context-menu interaction coverage, float-availability policy checks, and tiny-bounds drop-zone clamp regression coverage
   - Memory cleanup tests for cache boundedness and undock/rebuild cycles
   - Layout optimization tests for empty/single-child roots
 - ✅ `SnapFXTest` (44 tests) - Hide/Restore + Floating Window API behavior plus configurable shortcut behavior

ROADMAP.md

@@ -37,6 +37,7 @@ This roadmap lists planned work only; completed/fixed history is tracked in `CHA
 ### 1.1 Drag & Drop Improvements
 **Priority**: 🔴 Critical
 
+- ✅ **Tiny-bounds drop-zone stability**: Drop-zone edge sizing now avoids `Math.clamp` min/max-order exceptions during drag hover on very small bounds
 - 📋 No planned items; see `CHANGELOG.md` for completed fixes.
 
 ---

STATUS.md

@@ -5,7 +5,7 @@
 ## Build Status
 
 ✅ **Build**: `BUILD SUCCESSFUL`  
-✅ **Tests**: All 188 tests passing (latest full suite)
+✅ **Tests**: All 189 tests passing (latest full suite)
 ✅ **Module System**: Fully implemented (JPMS)  
 ✅ **Demo App**: Running successfully  
 ✅ **CI Automation**: GitHub Actions workflows added for push/PR tests and tag-triggered releases  
@@ -57,6 +57,7 @@
 - ✅ Unresolved drops always trigger floating fallback (not only outside main scene)
 - ✅ Main layout drops accept drags originating from floating windows
 - ✅ Escape cancels active drag reliably, including while the mouse button remains pressed
+- ✅ Drop-zone sizing now guards tiny bounds so drag hover never throws `Math.clamp` min/max-order exceptions
 
 ### Persistence (100% ✅)
 - ✅ JSON serialization (Gson)
@@ -127,7 +128,7 @@
 ### Testing (100% ✅)
 - ✅ DockGraphTest (56 tests, +11 regression tests)
 - ✅ DockLayoutSerializerTest (9 tests, +1 regression test)
-- ✅ DockLayoutEngineTest (28 tests) - Includes tab/header/splitter context-menu coverage and float-availability policy checks
+- ✅ DockLayoutEngineTest (29 tests) - Includes tab/header/splitter context-menu coverage, float-availability policy checks, and tiny-bounds drop-zone clamp regression coverage
 - ✅ **SnapFXTest (44 tests)** - Hide/Restore + Floating Window API tests plus configurable shortcut behavior
 - ✅ DockGraphSplitTargetDockingTest (1 test)
 - ✅ DockDragServiceTest (8 tests) - D&D visibility, tab-hover activation, float-detach callback behavior, and ESC drag-cancel handling
@@ -137,7 +138,7 @@
 - ✅ SimpleExampleTest (2 tests) - Stylesheet resource resolution behavior
 - ✅ MarkdownDocumentationConsistencyTest (12 tests) - Markdown consistency guardrails
 - ✅ AboutDialogTest (2 tests) - About dialog branding resources and credit link targets
-- ✅ **188/188 tests passing** ✅
+- ✅ **189/189 tests passing** ✅
 - ✅ **Performance tests for large layouts** (50+ nodes with stress move/cleanup operations)
 - ✅ **Memory leak cleanup tests** (cache boundedness, undock cleanup, large-layout detach/attach cycles)
 - ✅ **Edge case tests** (null inputs, detached nodes, invalid move targets, no-op revision checks)

src/main/java/com/github/beowolve/snapfx/view/DockLayoutEngine.java

@@ -791,10 +791,8 @@ private void addElementZones(DockElement element, Node view, Bounds bounds, int
         double zoneMin = isLeaf ? LEAF_DROP_ZONE_MIN_PX : DROP_ZONE_MIN_PX;
         double zoneMaxRatio = isLeaf ? LEAF_DROP_ZONE_MAX_RATIO : DROP_ZONE_MAX_RATIO;
 
-        double edgeW = Math.clamp(zoneBounds.getWidth() * zoneRatio,
-            zoneMin, zoneBounds.getWidth() * zoneMaxRatio);
-        double edgeH = Math.clamp(zoneBounds.getHeight() * zoneRatio,
-            zoneMin, zoneBounds.getHeight() * zoneMaxRatio);
+        double edgeW = calculateDropZoneEdgeSize(zoneBounds.getWidth(), zoneRatio, zoneMin, zoneMaxRatio);
+        double edgeH = calculateDropZoneEdgeSize(zoneBounds.getHeight(), zoneRatio, zoneMin, zoneMaxRatio);
 
         Bounds left = new BoundingBox(zoneBounds.getMinX(), zoneBounds.getMinY(), edgeW, zoneBounds.getHeight());
         Bounds right = new BoundingBox(zoneBounds.getMaxX() - edgeW, zoneBounds.getMinY(), edgeW, zoneBounds.getHeight());
@@ -814,6 +812,18 @@ private void addElementZones(DockElement element, Node view, Bounds bounds, int
         }
     }
 
+    private double calculateDropZoneEdgeSize(double span, double ratio, double minSize, double maxRatio) {
+        if (span <= 0) {
+            return 0;
+        }
+        double maxSize = span * maxRatio;
+        if (maxSize <= 0) {
+            return 0;
+        }
+        double normalizedMin = Math.min(minSize, maxSize);
+        return Math.clamp(span * ratio, normalizedMin, maxSize);
+    }
+
     private Bounds buildCenterBounds(Bounds bounds, double edgeW, double edgeH) {
         double innerW = bounds.getWidth() - (edgeW * 2);
         double innerH = bounds.getHeight() - (edgeH * 2);

src/test/java/com/github/beowolve/snapfx/view/DockLayoutEngineTest.java

@@ -5,6 +5,8 @@
 import com.github.beowolve.snapfx.model.*;
 import javafx.application.Platform;
 import javafx.event.Event;
+import javafx.geometry.BoundingBox;
+import javafx.geometry.Bounds;
 import javafx.geometry.Orientation;
 import javafx.scene.Node;
 import javafx.scene.control.Button;
@@ -26,6 +28,7 @@
 import org.testfx.framework.junit5.ApplicationTest;
 
 import java.lang.reflect.Field;
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -347,6 +350,16 @@ void testBuildSplitPane() {
         assertEquals(2, splitPane.getItems().size());
     }
 
+    @Test
+    void testAddElementZonesHandlesSmallLeafBoundsWithoutClampException() {
+        DockNode node = new DockNode(new Label("Test"), "Node");
+        List<DockDropZone> zones = new ArrayList<>();
+        Bounds tinyBounds = new BoundingBox(0, 0, 43.0, 43.0);
+
+        assertDoesNotThrow(() -> invokeAddElementZones(node, new StackPane(), tinyBounds, 0, zones));
+        assertEquals(5, zones.size());
+    }
+
     @Test
     void testSplitPaneContextMenuResetItemAppliesBalancedRatios() {
         DockNode node1 = new DockNode(new Label("Test1"), "Node 1");
@@ -681,4 +694,27 @@ private MouseEvent createPrimaryPressEvent(Node source, Node target) {
             new PickResult(target, 0, 0)
         );
     }
+
+    private void invokeAddElementZones(
+        DockElement element,
+        Node view,
+        Bounds bounds,
+        int depth,
+        List<DockDropZone> zones
+    ) {
+        try {
+            Method method = DockLayoutEngine.class.getDeclaredMethod(
+                "addElementZones",
+                DockElement.class,
+                Node.class,
+                Bounds.class,
+                int.class,
+                List.class
+            );
+            method.setAccessible(true);
+            method.invoke(layoutEngine, element, view, bounds, depth, zones);
+        } catch (ReflectiveOperationException e) {
+            throw new AssertionError("Unable to invoke DockLayoutEngine.addElementZones", e);
+        }
+    }
 }