some fixes in MainWindow move

modules/core_styles/styles/windows.otui

@@ -8,13 +8,18 @@ Window < UIWindow
   image-source: /core_styles/images/window.png
   image-border: 4
   image-border-top: 20
+  opacity: 1
   padding-top: 28
   padding-left: 16
   padding-right: 16
   padding-bottom: 16
+
   $disabled:
     color: #aaaaaa88
 
+  $pressed:
+    opacity: 0.8
+
 MainWindow < Window
   anchors.centerIn: parent
 

modules/core_widgets/uicheckbox.lua

@@ -10,5 +10,6 @@ end
 function UICheckBox:onMouseRelease(mousePos, mouseButton)
   if self:isPressed() and self:containsPoint(mousePos) then
     self:setChecked(not self:isChecked())
+    return true
   end
 end

modules/core_widgets/uiminiwindow.lua

@@ -10,6 +10,7 @@ function UIMiniWindow:onMousePress(mousePos, mouseButton)
   if parent:getClassName() ~= 'UIMiniWindowContainer' then
     self:raise()
   end
+  return true
 end
 
 function UIMiniWindow:onDragEnter(mousePos)

modules/core_widgets/uipopupmenu.lua

@@ -51,9 +51,8 @@ function UIPopupMenu:onMousePress(mousePos, mouseButton)
   -- clicks outside menu area destroys the menu
   if not self:containsPoint(mousePos) then
     self:destroy()
-    return true
   end
-  return false
+  return true
 end
 
 function UIPopupMenu:onKeyPress(keyCode, keyboardModifiers)

modules/core_widgets/uiwindow.lua

@@ -18,7 +18,8 @@ function UIWindow:onKeyPress(keyCode, keyboardModifiers)
 end
 
 function UIWindow:onMousePress(mousePos, mouseButton)
-
+  self:raise()
+  return true
 end
 
 function UIWindow:onDragEnter(mousePos)