Several widget fixes after optimizing repainting.

apps/progman/progman.c

@@ -593,4 +593,5 @@ int32_t appMain(DxeAppContextT *ctx) {
 
 void appShutdown(void) {
     shellUnregisterDesktopUpdate(desktopUpdate);
+    dvxQuit(sAc);
 }

core/dvxApp.c

@@ -1858,15 +1858,9 @@ static void handleMouseButton(AppContextT *ctx, int32_t mx, int32_t my, int32_t
                 } else {
                     ctx->lastTitleClickTime = now;
                     ctx->lastTitleClickId   = win->id;
-
-                    // Don't start a drag on a maximized window --
-                    // dragging clears the maximized flag, which
-                    // prevents the double-click restore from working.
-                    if (!win->maximized) {
                     wmDragBegin(&ctx->stack, hitIdx, mx, my);
                 }
             }
-            }
             break;
 
         case HIT_CLOSE:
@@ -2889,7 +2883,7 @@ static void pollKeyboard(AppContextT *ctx) {
 
             wclsClosePopup(closing);
 
-            wgtInvalidatePaint(closing);
+            wgtInvalidate(closing);
             continue;
         }
 
@@ -3011,6 +3005,7 @@ static void pollKeyboard(AppContextT *ctx) {
                             if (p->wclass && (p->wclass->flags & WCLASS_SCROLL_CONTAINER) &&
                                 wclsHas(p, WGT_METHOD_SCROLL_CHILD_INTO_VIEW)) {
                                 wclsScrollChildIntoView(p, next);
+                                wgtInvalidate(p);
                                 break;
                             }
                         }

core/dvxTypes.h

@@ -588,6 +588,9 @@ typedef struct {
     int32_t  dragWindow;
     int32_t  dragOffX;
     int32_t  dragOffY;
+    int32_t  dragStartX;   // mouse position at drag begin (for deadzone)
+    int32_t  dragStartY;
+    bool     dragActive;   // true once mouse moved past deadzone
     int32_t  resizeWindow;
     int32_t  resizeEdge;
     int32_t  scrollWindow;       // window being scroll-dragged (HIT_NONE = none)

core/dvxWm.c

@@ -1407,6 +1407,9 @@ void wmDragBegin(WindowStackT *stack, int32_t idx, int32_t mouseX, int32_t mouse
     stack->dragWindow = idx;
     stack->dragOffX   = mouseX - stack->windows[idx]->x;
     stack->dragOffY   = mouseY - stack->windows[idx]->y;
+    stack->dragStartX = mouseX;
+    stack->dragStartY = mouseY;
+    stack->dragActive = false;
 }
 
 
@@ -1435,11 +1438,28 @@ void wmDragEnd(WindowStackT *stack) {
 // we don't need to ask the app to repaint during the drag, just blit from
 // its buffer at the new position.
 
+#define DRAG_DEADZONE 4
+
 void wmDragMove(WindowStackT *stack, DirtyListT *dl, int32_t mouseX, int32_t mouseY, int32_t screenW, int32_t screenH) {
     if (stack->dragWindow < 0 || stack->dragWindow >= stack->count) {
         return;
     }
 
+    // Don't move until the mouse has moved past the deadzone from the
+    // initial click point. This allows double-clicks on the title bar
+    // without accidentally starting a drag.
+    if (!stack->dragActive) {
+        int32_t dx = mouseX - stack->dragStartX;
+        int32_t dy = mouseY - stack->dragStartY;
+
+        if (dx < -DRAG_DEADZONE || dx > DRAG_DEADZONE ||
+            dy < -DRAG_DEADZONE || dy > DRAG_DEADZONE) {
+            stack->dragActive = true;
+        } else {
+            return;
+        }
+    }
+
     WindowT    *win        = stack->windows[stack->dragWindow];
     int32_t     minVisible = 50;
 

core/widgetEvent.c

@@ -338,8 +338,17 @@ static void widgetOnMouseInner(WindowT *win, WidgetT *root, int32_t x, int32_t y
             // Click on popup area -- dispatch to widget's onMouse.
             // The widget may keep the popup open (e.g. scrollbar click)
             // or close it (item selection sets sOpenPopup = NULL).
-            wclsOnMouse(sOpenPopup, root, x, y);
+            WidgetT *popupWidget = sOpenPopup;
+            wclsOnMouse(popupWidget, root, x, y);
+
+            // If the popup closed, need a full repaint to erase the
+            // overlay (it's painted outside widget bounds).
+            if (!sOpenPopup) {
+                wgtInvalidate(root);
+            } else {
                 wgtInvalidatePaint(root);
+            }
+
             return;
         }
 
@@ -348,7 +357,7 @@ static void widgetOnMouseInner(WindowT *win, WidgetT *root, int32_t x, int32_t y
 
         wclsClosePopup(sOpenPopup);
         sOpenPopup = NULL;
-        wgtInvalidatePaint(root);
+        wgtInvalidate(root);
         // Fall through to normal click handling
     }
 

shell/shellApp.c

@@ -243,6 +243,15 @@ void shellForceKillApp(AppContextT *ctx, ShellAppT *app) {
         return;
     }
 
+    // Call shutdown hook so the app can unregister callbacks, close
+    // handles, etc. Without this, dangling function pointers (e.g.
+    // shellDesktopUpdate callbacks) cause crashes after dlclose.
+    if (app->shutdownFn) {
+        ctx->currentAppId = app->appId;
+        app->shutdownFn();
+        ctx->currentAppId = 0;
+    }
+
     // Destroy all windows belonging to this app. Walk backwards because
     // dvxDestroyWindow removes the window from the stack, shifting indices.
     for (int32_t i = ctx->stack.count - 1; i >= 0; i--) {

widgets/comboBox/widgetComboBox.c

@@ -163,7 +163,7 @@ void widgetComboBoxOnKey(WidgetT *w, int32_t key, int32_t mod) {
                 w->onChange(w);
             }
 
-            wgtInvalidatePaint(w);
+            wgtInvalidate(w);
             return;
         }
 

widgets/dropdown/widgetDropdown.c

@@ -135,6 +135,8 @@ void widgetDropdownOnKey(WidgetT *w, int32_t key, int32_t mod) {
             if (w->onChange) {
                 w->onChange(w);
             }
+
+            wgtInvalidate(w);
         } else if (key >= 0x20 && key < 0x7F) {
             int32_t found = widgetTypeAheadSearch((char)key, d->items, d->itemCount, d->hoverIdx);
 

widgets/radio/widgetRadio.c

@@ -44,6 +44,7 @@ typedef struct {
 // Prototypes
 // ============================================================
 
+static void invalidateOldSelection(WidgetT *group, int32_t oldIdx);
 static void widgetRadioDestroy(WidgetT *w);
 static void widgetRadioGroupDestroy(WidgetT *w);
 void widgetRadioOnMouse(WidgetT *w, WidgetT *root, int32_t vx, int32_t vy);
@@ -150,6 +151,7 @@ void widgetRadioOnKey(WidgetT *w, int32_t key, int32_t mod) {
             if (next) {
                 RadioDataT *nd      = (RadioDataT *)next->data;
                 RadioGroupDataT *gd = (RadioGroupDataT *)next->parent->data;
+                invalidateOldSelection(w->parent, gd->selectedIdx);
                 sFocusedWidget = next;
                 gd->selectedIdx = nd->index;
 
@@ -174,6 +176,7 @@ void widgetRadioOnKey(WidgetT *w, int32_t key, int32_t mod) {
             if (prev) {
                 RadioDataT *pd      = (RadioDataT *)prev->data;
                 RadioGroupDataT *gd = (RadioGroupDataT *)prev->parent->data;
+                invalidateOldSelection(w->parent, gd->selectedIdx);
                 sFocusedWidget = prev;
                 gd->selectedIdx = pd->index;
 
@@ -192,6 +195,21 @@ void widgetRadioOnKey(WidgetT *w, int32_t key, int32_t mod) {
 // widgetRadioOnMouse
 // ============================================================
 
+// Find the currently selected radio in the group and invalidate it
+static void invalidateOldSelection(WidgetT *group, int32_t oldIdx) {
+    for (WidgetT *c = group->firstChild; c; c = c->nextSibling) {
+        if (c->type == sRadioTypeId) {
+            RadioDataT *rd = (RadioDataT *)c->data;
+
+            if (rd->index == oldIdx) {
+                wgtInvalidatePaint(c);
+                return;
+            }
+        }
+    }
+}
+
+
 void widgetRadioOnMouse(WidgetT *w, WidgetT *root, int32_t vx, int32_t vy) {
     (void)root;
     (void)vx;
@@ -201,6 +219,11 @@ void widgetRadioOnMouse(WidgetT *w, WidgetT *root, int32_t vx, int32_t vy) {
     if (w->parent && w->parent->type == sRadioGroupTypeId) {
         RadioDataT *rd      = (RadioDataT *)w->data;
         RadioGroupDataT *gd = (RadioGroupDataT *)w->parent->data;
+
+        if (gd->selectedIdx != rd->index) {
+            invalidateOldSelection(w->parent, gd->selectedIdx);
+        }
+
         gd->selectedIdx = rd->index;
 
         if (w->parent->onChange) {

widgets/tabControl/widgetTabControl.c

@@ -414,17 +414,19 @@ void widgetTabControlPaint(WidgetT *w, DisplayT *d, const BlitOpsT *ops, const B
 
         td->scrollOffset = clampInt(td->scrollOffset, 0, maxOff);
 
-        uint32_t fg = colors->contentFg;
+        bool canScrollLeft  = (td->scrollOffset > 0);
+        bool canScrollRight = (td->scrollOffset < maxOff);
         BevelStyleT btnBevel = BEVEL_RAISED(colors, 1);
 
         // Left arrow button
         drawBevel(d, ops, w->x, w->y, TAB_ARROW_W, tabH, &btnBevel);
         {
+            uint32_t arrowFg = canScrollLeft ? colors->contentFg : colors->windowShadow;
             int32_t  cx      = w->x + TAB_ARROW_W / 2;
             int32_t  cy      = w->y + tabH / 2;
 
             for (int32_t i = 0; i < 4; i++) {
-                drawVLine(d, ops, cx - 2 + i, cy - i, 1 + i * 2, fg);
+                drawVLine(d, ops, cx - 2 + i, cy - i, 1 + i * 2, arrowFg);
             }
         }
 
@@ -432,11 +434,12 @@ void widgetTabControlPaint(WidgetT *w, DisplayT *d, const BlitOpsT *ops, const B
         int32_t rx = w->x + w->w - TAB_ARROW_W;
         drawBevel(d, ops, rx, w->y, TAB_ARROW_W, tabH, &btnBevel);
         {
+            uint32_t arrowFg = canScrollRight ? colors->contentFg : colors->windowShadow;
             int32_t  cx      = rx + TAB_ARROW_W / 2;
             int32_t  cy      = w->y + tabH / 2;
 
             for (int32_t i = 0; i < 4; i++) {
-                drawVLine(d, ops, cx + 2 - i, cy - i, 1 + i * 2, fg);
+                drawVLine(d, ops, cx + 2 - i, cy - i, 1 + i * 2, arrowFg);
             }
         }
     }
@@ -451,6 +454,9 @@ void widgetTabControlPaint(WidgetT *w, DisplayT *d, const BlitOpsT *ops, const B
     int32_t oldClipH = d->clipH;
     setClipRect(d, headerLeft, w->y, headerRight - headerLeft, tabH + 2);
 
+    // Clear the header strip so scrolled-away tab pixels are erased
+    rectFill(d, ops, headerLeft, w->y, headerRight - headerLeft, tabH + 2, colors->contentBg);
+
     int32_t tabX   = headerLeft - td->scrollOffset;
     int32_t tabIdx = 0;