After set an opened Combo Box to invisible, no response from the entire window.

Here's a window, with a button and a ComboBox in it.


```D
if (nk_begin(ctx, "test_window",nk_rect(600,100,260,300),NK_WINDOW_BORDER|NK_WINDOW_MOVABLE|NK_WINDOW_TITLE))
{
/* Button */
nk_layout_row_dynamic(ctx, 35, 1);
if(nk_button_label(ctx, "Button"))
{
printf("button\n");
}

/* Combo */
if (isShowComboBox)
{
if(nk_combo_begin_label(ctx, "Demo Combo",nk_vec2(300, 100)))
{
nk_layout_row_dynamic(ctx, 18, 1);
nk_combo_item_label(ctx, "combo_item_label2", NK_TEXT_LEFT);
nk_combo_item_label(ctx, "combo_item_label2", NK_TEXT_LEFT);
nk_combo_end(ctx);
}
}
}
nk_end(ctx);
```

The flag `isShowComboBox` is used to control whether the combo is visible。
Use a Key to set value of `isShowComboxBox` , true or false. Leave the Combo open, then I set the `isShowComboBox` to false. So, from the next frame, combo disappear as expected.
Set isShowComBox = true again, the combo is visiable, But all the things in the window have no response to my input, can't click Button, can't move window, can't open the content of ComboBox.

When this happen, I click or just move the mouse in other nuklear windows, and back to this window, everything return normal.

Reproduce the issue using the shown nk_combo_begin_label and nk_combo_end sequence, leaving the combo open while toggling isShowComboBox. Start by tracing combo state and input handling across the frame where the combo is hidden and shown again. Done means the window remains responsive: its button, movement, and combo opening work immediately after the combo is restored.

Written by the indexing model from the issue text.