Maxthon 2.5.15.55 Beta

* User Interface
- fixed flickering problem of Customize dialog
- fixed problem that context menu popup after switching tab with right mouse down + mouse wheel
- fixed mouse gesture trail problem while switching tab with right mouse down + mouse wheel
- fixed problem that Maxthon may move to the front while loading certain webpages on background

* Browsing
- fixed Last Visited Pages problem that middle click does not work for local file links

* Screen Capture
- fixed image saving and file extension problem

* History
- fixed history item delete problem

* Safety
- fixed a problem which may generate kernel32.dll in Maxthon installation folder

* Others
- fixed random crash problem when dialogs popup
- fixed problem that visiting pages are not saved when Maxthon is closed by Maxthon Installer