New features
Better integration with the Windows operating system

• Windows 7:
• Aero Glass
• Aero Peek
• Jump Lists

Opera Carakan JavaScript engine

• Cross-platform bytecode interpreter for a new register-based instruction set
• Internal object model with automatic classification and inline property caching
• Machine code generation (JIT compiler)
• Divided garbage collection heap: automatically traverses the memory of active heaps
• Caching of compiled programs
• Reduced memory usage
• Additional Carakan information (http://my.opera.com/core/blog/2009/12/22/carakan-revisited)

Opera "O" tab and menu
The new Opera "O" tab and its associated menu (located on the left side of the Opera Tab bar) replaces the traditional Opera Menu bar. This increases vertical space in the Opera desktop window, and centralizes frequently used features and tools in one, convenient location. Optionally, the new Opera "O" tab and menu can be replaced with the traditional Opera Menu bar by clicking "Show Menu Bar" in the Opera "O" menu. This new Opera feature contains the following items.

• Tabs and Windows ?
• Page ?
• Print ?
• Bookmarks ?
• History
• Downloads
• Opera Unite ?
• Synchronize Opera ?
• Widgets ?
• Notes
• Mail and Chat Accounts
• Mail ?
• Contacts
• Appearance
• Settings ?
• Help ?
• Show Menu Bar
• Exit

Opera Presto 2.5 rendering engine
Opera 10.50 (with Opera Widgets for Desktop) for Windows contains the latest Opera rendering engine: Opera Presto 2.5, and incorporates the following features.
CSS
Support is added for:

• CSS 2.1 visibility: collapse
• See: W3C section 11.2 Visibility: the visibility property (http://www.w3.org/TR/CSS2/visufx.html#visibility)
• CSS3 border-radius property (rounded corners)
• See: W3C section 4.4. The border-radius properties (http://www.w3.org/TR/css3-background/#the-border-radius)
• CSS3 Backgrounds and Borders
• See: W3C CSS Backgrounds and Borders Module Level 3 (http://www.w3.org/TR/css3-background/)
• CSS3 2D Transforms
• See: W3C CSS 2D Transforms Module Level 3 (http://www.w3.org/TR/css3-2d-transforms/)
• CSS3 Transitions
• See: W3C CSS Transitions Module Level 3 (http://www.w3.org/TR/css3-transitions/)

HTML5
Support is added for:

• HTML5 <video> element DOM APIs to reflect changes in the specification
• See: W3C section 4.8.7 The video element (http://www.w3.org/TR/html5/video.html)
• HTML5 <video> seeking; enables seeking through videos that are not completely downloaded
• See: W3C section 4.8.10.9 Seeking (http://www.w3.org/TR/html5/video.html#dom-media-seeking)
• HTML5 <param> element (child of the HTML5 <object> element) support for controlling animations/scripts
• See: W3C Section B Object <param> attributes defined in WICD Core (http://www.w3.org/TR/WICD/#param-elements)
• See: W3C WICD 1.0 TestSuite and Implementation Matrix (http://www.w3.org/2004/CDF/TestSuite/WICD_CDR_WP1/)

SVG
Support is added for:

• SVG buffered-rendering property
• See: W3C section 11.10.5 The buffered-rendering property (http://www.w3.org/TR/SVGTiny12/painting.html#BufferedRenderingProperty)
• Text search inside SVG
• See: W3C section 10.14 Text search (http://www.w3.org/TR/SVGMobile12/text.html#TextSearch)
• Animated raster images (APNG, GIF) in all the SVG elements that support raster graphics, i.e., <image>, <foreignObject>, and <feImage>
• See: W3C section 2.2.4 Animation (http://www.w3.org/TR/SVGTiny12/concepts.html#Animation)
• See: W3C section 16.2 Animation elements (http://www.w3.org/TR/SVGTiny12/animate.html#Animation.class)

Opera Vega graphics library

• Renders all graphics in Opera
• Employs rounded corners, box shadow, animations, etc.
• Contains improved support for SVG and the HTML 5 <canvas> element
• Additional Vega information (http://my.opera.com/core/blog/2009/02/04/vega)

Opera Widgets for Desktop
Although they run outside the browser, Opera Widgets have been treated as entities inside the browser in many respects. The new Opera Widgets for Desktop ends this dependency on the browser and moves Opera Widgets to the next level: that of first-class applications. Above all, Opera Widgets for Desktop gives widgets the potential to replace some native applications on the computer.
Opera Widgets for Desktop includes the following features:

• Support for View Modes through the W3C Widgets Module API:
• See: W3C Widgets 1.0: View Modes Media Feature (http://www.w3.org/TR/widgets-vmmf/)
• A Widget menu located within the new Opera "O" menu, or optionally from the traditional Opera Menu toolbar. Menu options include:
• Get Widgets
• Manage Widgets... (opens the Widgets panel in the Opera user interface)
• What are Opera Widgets?
• Widget lifespans are separated from the Opera desktop browser.
• Each widget runs in a separate process.
• Integration with the operating system includes support for creating desktop and menu-based application shortcuts.
• Widget control buttons organize important actions:
• Move
• Close
• Minimize
• Settings
• Support is provided for different widget modes such as "Application" and "Widget".
• A new widget installation/uninstallation process is supported:
• Uninstallation from "Add/Remove Programs" in the Windows Control Panel
• Notification pop-ups are supported.
• Password manager is supported.
• File I/O (Input/Output) access is supported.
• The upgrading of installed widgets from current to new runtime is supported.
• Improved support for Opera Dragonfly is provided.
• Remote debugging is possible; configurable via a widget's context menu.

Download acceleration software compatibility

• Support is added for download acceleration software (user option), which integrates a user's favorite download accelerator with Opera.
• Check box activation is located at: opera:config#UserPrefs|UseExternalDownloadManager

Non-modal notification messages

• Notification message windows no longer interrupt workflow
• JavaScript alerts, HTTP notifications, password manager, etc., now display as page overlays.
• Switching of tabs or windows while these dialogs are displayed is now allowed.

Private browsing

• Creating, browsing, and then closing private tabs and private windows removes all records of Web sites visited through them.
• Using the new Opera "O" tab and menu, go to:
• Tabs and Windows > New Private Tab
• Tabs and Windows > New Private Window
• Using the traditional Opera Menu bar, go to:
• File > New Private Tab
• File > New Private Window

Web Storage

• Support is established for:
• Session storage: offers a temporary storage of data
• Warning dialogs when exceeding storage quotas for web storage
• The user can increase, or set unlimited quotas for web storage
• Local storage: stores data for a longer period until the user explicitly clears it
• The Address field autocomplete list now includes opera:webstorage
• Added a "Delete Web storage databases" check box item in the "Delete private data" detailed options dialog
• See: W3C Web Storage Working Draft (http://www.w3.org/TR/webstorage/)

Web SQL Database

• Support is established for:
• Storage of data in a more structured manner
• Querying data using SQL
• Warning dialogs when exceeding storage quotas for web database
• The user can increase, or set unlimited quotas for web database
• Added a "Delete Web storage databases" check box item in the "Delete private data" detailed options dialog
• The Address field autocomplete list now includes opera:webdatabases
• See: W3C Web SQL Database WWorking Draft (http://www.w3.org/TR/webdatabase/)

Changes since Opera 10.50 beta 2 (with Opera Widgets for Desktop)
User interface
Added

• Download acceleration software compatibility (user option); integrates a user's favorite download acceleration software with Opera
• Check box activation located at: opera:config#UserPrefs|UseExternalDownloadManager
• A keyboard shortcut for new private windows: Ctrl+Shift+N
• Support for View Modes through the W3C Widgets Module API:
• See: W3C Widgets 1.0: View Modes Media Feature (http://www.w3.org/TR/widgets-vmmf/)

Improved

• Created a visual design to distinguish between private and non-private windows
• Removed hardcoded icons from HTML5 <input> elements
• Skins can now specify the system color scheme as default
• Changed the private mode icon in the context menu
• Translations have been updated in Opera Unite applications

Fixed

• A white line appearing between a maximized Opera window and the Vista/Windows 7 taskbar
• Closing tabs from the Task bar leaving a ghost tab in the Task bar list
• Opera Link only partially synchronizing data (bookmarks)
• A problem when restarting Opera with "Manage bookmarks" and one or more tabs open
• Windows Media Player plug-in not initializing
• An issue when enabling the print preview option
• Data loss occuring when shutting down the computer while Opera is still closing
• Context menus not appearing in source view
• A problem when opening a private tab
• Only part of a page being visible with Aero Peek after zooming in
• A problem when correcting spelling with the keyboard in single-line form fields
• Several tab-modal dialog problems
• Minimized tabs not resizing to window when activated
• Minimized tabs not displaying after restart
• Popups being dragged out and not being able to be brought back in
• Non-modal dialogs disappearing into the browser chrome
• Pop-up windows not being skinnable
• Gmail not working in private browsing mode
• A problem setting an image on a Web page as a Speed Dial background via the context menu
• Switching the color scheme from "Windows Aero" to "Windows Vista Basic" and back again corrupts title bar
• A scrolling issue which freezes the user interface
• Opera Turbo not working correctly
• An issue with "Find in page" search if search string starts with a space
• Several issues with Adobe Shockwave

Display and scripting
Added

• Video seeking
• Now possible to seek through videos that are not completely downloaded
• When skipping forward, unwanted sections will not be downloaded
• See: W3C section 4.8.7 The video element (http://www.w3.org/TR/html5/video.html)

Improved

• Numerous updates to the Carakan JavaScript engine
• JavaScript resize clipping, and automatic maximizing of restored tabs and child windows
• The DEP (Data Execution Prevention) message

Fixed

• An issue when disconnecting from Opera Dragonfly remote debug mode
• A problem when embedding with SVG content
• Uninitialized data being displayed when using content blocking
• Several issues with Microsoft Silverlight
• An issue with WinXP toolbar integration
• A potential memory leak in context menus
• An issue with User JS and Browser JS

Mail, news, chat
Added

• Support for localized webfeeds and webmail providers

Fixed

• Absense of context menus for the fields: To, CC, Subject, etc.
• Attachments being displayed multiple times after deleting mail
• Occasionally opening mails in new windows shows a blank mail window
• An issue when replying to an e-mail
• A problem when double-clicking on "Sent" mail

Network
Added

• <video> seeking using HTTP byte range requests
• Created HTTP range based cache subsystem to support <audio> and <video>

Fixed

• Various issues with Opera Widgets
• A firewall alert occurring when starting Opera on Windows 7

Security
Fixed

• Fixed vulnerability in Renegotiation feature of the TLS protocol
• See our advisory (http://www.opera.com/support/search/view/944/)
• See our Opera Security blog article (http://my.opera.com/securitygroup/blog/2010/01/23/alpha-testing-tls-renego-fix)
• For your reference, this security fix was implemented in the Opera 10.50 (with Opera Widgets for Desktop) beta 1 for Windows release on February 11, 2010.
• Fixed a moderately severe security issue; details will be disclosed at a later date.