user32: Only update listbox horizontal scroll info if WS_HSCROLL is set.

dlls/user32/listbox.c

@@ -265,17 +265,14 @@ static void LISTBOX_UpdateScroll( LB_DESCR *descr )
         if (descr->style & WS_VSCROLL)
             SetScrollInfo( descr->self, SB_VERT, &info, TRUE );
 
-        if (descr->horz_extent)
+        if (descr->style & WS_HSCROLL)
         {
-            info.nMin  = 0;
-            info.nMax  = descr->horz_extent - 1;
             info.nPos  = descr->horz_pos;
             info.nPage = descr->width;
-            info.fMask = SIF_RANGE | SIF_POS | SIF_PAGE;
+            info.fMask = SIF_POS | SIF_PAGE;
             if (descr->style & LBS_DISABLENOSCROLL)
                 info.fMask |= SIF_DISABLENOSCROLL;
-            if (descr->style & WS_HSCROLL)
-                SetScrollInfo( descr->self, SB_HORZ, &info, TRUE );
+            SetScrollInfo( descr->self, SB_HORZ, &info, TRUE );
         }
     }
 }
@@ -1241,14 +1238,19 @@ static LRESULT LISTBOX_SetHorizontalExtent( LB_DESCR *descr, INT extent )
 {
     if (descr->style & LBS_MULTICOLUMN)
         return LB_OKAY;
-    if (extent <= 0) extent = 1;
     if (extent == descr->horz_extent) return LB_OKAY;
     TRACE("[%p]: new horz extent = %d\n", descr->self, extent );
     descr->horz_extent = extent;
+    if (descr->style & WS_HSCROLL) {
+        SCROLLINFO info;
+        info.cbSize = sizeof(info);
+        info.nMin  = 0;
+        info.nMax = descr->horz_extent ? descr->horz_extent - 1 : 0;
+        info.fMask = SIF_RANGE;
+        SetScrollInfo( descr->self, SB_HORZ, &info, TRUE );
+    }
     if (descr->horz_pos > extent - descr->width)
         LISTBOX_SetHorizontalPos( descr, extent - descr->width );
-    else
-        LISTBOX_UpdateScroll( descr );
     return LB_OKAY;
 }
 

dlls/user32/tests/listbox.c

@@ -1621,6 +1621,8 @@ static void test_extents(void)
 {
     HWND listbox, parent;
     DWORD res;
+    SCROLLINFO sinfo;
+    BOOL br;
 
     parent = create_parent();
 
@@ -1629,11 +1631,25 @@ static void test_extents(void)
     res = SendMessageA(listbox, LB_GETHORIZONTALEXTENT, 0, 0);
     ok(res == 0, "Got wrong initial horizontal extent: %u\n", res);
 
+    sinfo.cbSize = sizeof(sinfo);
+    sinfo.fMask = SIF_RANGE;
+    br = GetScrollInfo(listbox, SB_HORZ, &sinfo);
+    ok(br == TRUE, "GetScrollInfo failed\n");
+    ok(sinfo.nMin == 0, "got wrong min: %u\n", sinfo.nMin);
+    ok(sinfo.nMax == 100, "got wrong max: %u\n", sinfo.nMax);
+
     SendMessageA(listbox, LB_SETHORIZONTALEXTENT, 64, 0);
 
     res = SendMessageA(listbox, LB_GETHORIZONTALEXTENT, 0, 0);
     ok(res == 64, "Got wrong horizontal extent: %u\n", res);
 
+    sinfo.cbSize = sizeof(sinfo);
+    sinfo.fMask = SIF_RANGE;
+    br = GetScrollInfo(listbox, SB_HORZ, &sinfo);
+    ok(br == TRUE, "GetScrollInfo failed\n");
+    ok(sinfo.nMin == 0, "got wrong min: %u\n", sinfo.nMin);
+    ok(sinfo.nMax == 100, "got wrong max: %u\n", sinfo.nMax);
+
     DestroyWindow(listbox);
 
 
@@ -1642,11 +1658,37 @@ static void test_extents(void)
     res = SendMessageA(listbox, LB_GETHORIZONTALEXTENT, 0, 0);
     ok(res == 0, "Got wrong initial horizontal extent: %u\n", res);
 
+    sinfo.cbSize = sizeof(sinfo);
+    sinfo.fMask = SIF_RANGE;
+    br = GetScrollInfo(listbox, SB_HORZ, &sinfo);
+    ok(br == TRUE, "GetScrollInfo failed\n");
+    ok(sinfo.nMin == 0, "got wrong min: %u\n", sinfo.nMin);
+    ok(sinfo.nMax == 100, "got wrong max: %u\n", sinfo.nMax);
+
     SendMessageA(listbox, LB_SETHORIZONTALEXTENT, 64, 0);
 
     res = SendMessageA(listbox, LB_GETHORIZONTALEXTENT, 0, 0);
     ok(res == 64, "Got wrong horizontal extent: %u\n", res);
 
+    sinfo.cbSize = sizeof(sinfo);
+    sinfo.fMask = SIF_RANGE;
+    br = GetScrollInfo(listbox, SB_HORZ, &sinfo);
+    ok(br == TRUE, "GetScrollInfo failed\n");
+    ok(sinfo.nMin == 0, "got wrong min: %u\n", sinfo.nMin);
+    ok(sinfo.nMax == 63, "got wrong max: %u\n", sinfo.nMax);
+
+    SendMessageA(listbox, LB_SETHORIZONTALEXTENT, 0, 0);
+
+    res = SendMessageA(listbox, LB_GETHORIZONTALEXTENT, 0, 0);
+    ok(res == 0, "Got wrong horizontal extent: %u\n", res);
+
+    sinfo.cbSize = sizeof(sinfo);
+    sinfo.fMask = SIF_RANGE;
+    br = GetScrollInfo(listbox, SB_HORZ, &sinfo);
+    ok(br == TRUE, "GetScrollInfo failed\n");
+    ok(sinfo.nMin == 0, "got wrong min: %u\n", sinfo.nMin);
+    ok(sinfo.nMax == 0, "got wrong max: %u\n", sinfo.nMax);
+
     DestroyWindow(listbox);
 
     DestroyWindow(parent);