Sleipnir 4 for Windows Technology & Design Build Release Announcement

category : for Windows, Sleipnir 4

This is a Sleipnir 4 for Windows Technology & Design Build release announcement.

In today’s release of Sleipnir for Windows we have focused on implemented the most important functions that have been requested by users. We are dealing with matters that we could not do with Sleipnir 3 to provide users of Sleipir 2 and Sleipnir and users of other Web browsers who feel that there is something lacking a Web browser that they feel they can choose.

This release is restricted to being a blog only archive version, but it is of a quality that can be used for your everyday browsing. (The release of the installer version and the update notification to users already using Sleipnir 3 is scheduled to be released next time)

・Download the Sleipnir 4 for Windows Technology & Design Build

Optimized speed and cut memory usage

Lightweight by new UI

The memory and resource usage, and the CPU load have been reduced, improving the start-up speed by approximately 10%. Operations after start-up such as tab switching has also become lighter. (Speed optimization will continue to be adjusted until the official release)

Mode selection by operating environment

The way threads and processes are used have been optimized depending on the number of core processors and implemented memory used. This feature reduces the memory usage and CPU load.

Faster updating

We have made improvements for optimized the speed of updating. The updating time has been reduced to between a half and third of before.

(Manually setting for Trident and WebKit possible)

Renewed UI design and tool bar icons

To improve the visual recognition of Aero Grass, we have removed a vast area of Aero Grass in the design and changed the icons to be easier to distinguish. (Please understand that there may be some final changes made to the design before the official release)

(A new design balancing lightweight usage and easy to understand design)

Quick security for WebKit and Trident implemented

We have also taken another look at UI and usage of quick security. Values are now set from Customize|Security. In addition to the status bar, temporary switching can now also be done from the tool bar.

(The values that can be set differ between WebKit and Trident)

Traverse search (Temporary name, scheduled to be released in Sleipnir 4 Final Build)

Using search keywords, it is now possible to perform searches taken from bookmarks and your history in Sleipnir, and we are also planning to implement the pick-up searching you might be used to in Sleipnir Mobile for Android.

(This is a prototype version so there may be some major changes made to the UI and specification)

Improved operationability

Unified operations when using with keyboard

Up until now, it has been possible to control how links are opened in the browser with Ctrl+click, Shift+click and the center button, but you can now also use these operations for controlling the bookmarks bar, bookmarks and your history. This is especially great for users who customize so that the browser does not open links in new tabs.

Mouse gesture track

We have set the mouse track to be displayed when using mouse gestures. (Currently excludes touch gesturing)This function can be set to ON / OFF from the customization dialog.

Other modifications

– Homepage set to be displayed when all tabs are closed
– Area that can be dragged with mouse whe moving through form extended
– Area that is displayed in the right-click menu of the tool bar extended
– Tree display being opened when adding bookmarks fixed
– Menu and button menu changed


Smart tabs for achieving intuitive tab actions implemented

Sleipnir is well known for its “easy to use and customizable tabs”, but there has been operations that can not be followed with customization alone, so we have added smart tabs for better management of tabs. Smart tabs cleverly manage adding and removing of tabs.

Fenrir Pass Connect settings now as submenu

We have improved visual recognition and operationability of the menu by adding a sub-menu.

Improved drag and dropping from Sleipnir UI and external applications

A number of drag and drop functions such as from address bar to browser and bookmark panel to desktop have been added.

The precious data protecting restore function made more powerful

The data restoration function is automatically executed when bookmark or tab data is erased. It is also possible to manually select past back-up data from the dialog if the restoration function does not execute. It is also possible to restore the tabs in the previous session when Sleipnir unexpectedly terminates.

(Not only can you restore back to immediately before, but also to a few days before)

Refresh/Stop button merged

We have merged the refresh and stop buttons, and have removed it from the address bar which makes it possible to place it where you like.

For advanced users

Change the cache folder for WebKit

We have made it possible to declare WebKit start-up parameters so that you can change the WebKit engine cache folder.

/Example of saving to user.ini/


Customize track

The color and width of mouse gesture tracks can be adjusted.

/Default value/


/Example of saving to user.ini ~ Orange colour + Thick line/


Regarding UI customization

It may not  be to the extent that “you think you can break it by touching it with your fingers” like with Sleipnir for Mac, but using UI customization in Sleipnir for Windows, you can make use of a large area of the browser. You can actually remove even more but to balance it with ease of use, we think this is about right.

(Comparison showing when using 2 level display with tab bar and address bar)

Please try out the evolved Sleipnir for Windows.

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