Fix slow keyboard when double tap not disabled (#4711)

[fix, UX] Fix slow keyboard when double tap not disabled

When double tap is not disabled (only ensured in ReaderRolling),
repeated key hits were slowed down by it. This ensures
Input widgets that temporarily overrides it to be disabled
are satisfied.

frontend/ui/uimanager.lua

@@ -318,8 +318,9 @@ function UIManager:close(widget, refreshtype, refreshregion, refreshdither)
     widget:handleEvent(Event:new("FlushSettings"))
     -- first send close event to widget
     widget:handleEvent(Event:new("CloseWidget"))
-    -- make it disabled by default and check any widget that enables it
+    -- make it disabled by default and check if any widget wants it disabled or enabled
     Input.disable_double_tap = true
+    local requested_disable_double_tap = nil
     -- then remove all references to that widget on stack and refresh
     for i = #self._window_stack, 1, -1 do
         if self._window_stack[i].widget == widget then
@@ -333,11 +334,15 @@ function UIManager:close(widget, refreshtype, refreshregion, refreshdither)
                 logger.dbg("Lower widget", self._window_stack[i].widget.name or self._window_stack[i].widget.id or tostring(self._window_stack[i].widget), "was dithered, honoring the dithering hint")
             end
 
-            if self._window_stack[i].widget.disable_double_tap == false then
-                Input.disable_double_tap = false
+            -- Set double tap to how the topmost specifying widget wants it
+            if requested_disable_double_tap == nil and self._window_stack[i].widget.disable_double_tap ~= nil then
+                requested_disable_double_tap = self._window_stack[i].widget.disable_double_tap
             end
         end
     end
+    if requested_disable_double_tap ~= nil then
+        Input.disable_double_tap = requested_disable_double_tap
+    end
     if dirty and not widget.invisible then
         -- schedule remaining widgets to be painted
         for i = 1, #self._window_stack do