Open two instances of a file in a single Visual Studio session

Here's how to do it...

Select the tab you want two copies of Select menu Window → New Window from the menu. Right click the new tab and select New Vertical Tab Group

If New Window is not listed in the *Window menu note that the command does exist, even as of Visual Studio 2017. Add it to the Window menu using menu Tools → Customize → Commands. At that point decide where to put the New Window command and select Add Command.

UPDATED on "30 July 2018"

In Visual Studio Code version 1.25.1 and later

Way 1

You can simple left click on your file in the side-panel (explorer) and press Ctrl + Enter.

Way 2

Simply right click on your file in the Visual Studio Code side-panel (explorer) and select the first option open to the side.

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For Visual Basic, HTML and JScript and RDL Expression, the Window > New Window option mentioned in PaulB's answer is disabled. However an option can be changed in the Registry to enable the menu item.

All other languages do not restrict to a single code window so you can use PaulB's answer without editing the registry.

Enabling New Window in Windows Registry.^{[1] [2]}

Go to the following registry key. This example is for Basic (Visual Basic), but the key is also there for HTML, JScript and RDL Expression. 64-bit OS: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\VisualStudio\10.0\Languages\Language Services\Basic 32-bit OS: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\10.0\Languages\Language Services\Basic Find the value Single Code Window Only and do one of the following: Set it to 0 Rename the value Delete the value (use caution!)

This will enable the "New Window" menu item, but it may still not be visible in the menu.

Adding Menu Item

To actually see the New Window menu item I had to add it back into the menu:

Tools > Customize... > Commands > Add Command...

Select 'Menu Bar' the select the 'Window' menu in the dropdown

Add Command... > Window > New Window > OK

Restoring Registry Value Copy-paste this to notepad, save as a .reg file and import the file into your registry to restore the initial setting.

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\VisualStudio\10.0\Languages\Language Services\Basic]
"Single Code Window Only"=dword:00000001

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Go to menu → Windows → New Window:

https://i.stack.imgur.com/cJplN.png

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You can use the Windows → New Window option to duplicate the current window. See more at: Why I like Visual Studio 2010? Undock Windows

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Open the file (if you are using multiple tab groups, make sure your file is selected).

Menu Window → Split (alternately, there's this tiny nub just above the editor's vertical scroll bar - grab it and drag down)

This gives you two (horizontal) views of the same file. Beware that any edit-actions will reflect on both views.

Once you are done, grab the splitter and drag it up all the way (or menu Window → Remove Split).

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How to open two instances of the same file side by side in Visual Studio 2019:

Open the file. Click Window -> New Window. A new window should be open with the same file. Click on Window -> New Vertical Document Group.

https://i.stack.imgur.com/TUGN5.png

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With the your file opened, go to command window (menu View → Other Windows → Command window, or just Ctrl + Alt + A)

Type:

Window.NewWindow

And then

Window.NewVerticalTabGroup

worked for me (Visual Studio 2017).

Or using menus:

Menu Window → New Window

Menu Window → New vertical tap group

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Luke's answer didn't work for me. The 'New Window' command was already listed in the customize settings, but not showing up in the .js tabs context menu, despite deleting the registry setting.

So I used:

Tools

Customize...

Keyboard...

Scroll down to select Window.NewWindow

And I pressed and assigned the shortcut keys, Ctrl + Shift + W.

That worked for me.

==== EDIT ====

Well, 'worked' was too strong. My keyboard shortcut does indeed open another tab on the same JavaScript file, but rather unhelpfully it does not render the contents; it is just an empty white window! You may have better luck.

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Window menu, New Horizontal/Vertical Tab Group there will do, I think.

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When working with Visual Studio 2013 and VB.NET I found that you can quite easily customize the menu and add the "New Window" command - there is no need to mess with the registry!

God only knows why Microsoft chose not to include the command for some languages...?

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For newer versions (such as Visual Studio 2017)

Select the window you want to duplicate.

Go to the window tab and click on split at the top of the list.

When you are done, click it again to toggle it off.

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For file types, where the same file can't be opened in a vertical tab group (for example .vb files) you can

Open 2 different instances of Visual Studio

Open the same file in each instance

Resize the IDE windows & place them side by side to achieve your layout.

If you save to disk in one instance though, you'll have to reload the file when you switch to the other. Also if you make edits in both instances, you'll have to resolve on the second save. Visual Studio prompts you in both cases with various options. You'll simplify your life a bit if you edit in only the one instance.

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I don't have a copy of Visual Studio 2005, but this process works on Visual Studio 2008:

Open xyz.cpp along with some other file. Right click on tab header and select new vertical tab group. Left click on that other file in the first tab group. Open xyz.cpp through solution explorer again.

You should now have two instances of file in separate vertical tab groups.

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https://i.stack.imgur.com/EDELN.jpg

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I came up with a hack that might produce the result intended in the original answer.

If you have the file you want in two windows in a source control, you can right-click on the file and select compare, you can compare the

If you do compare you will have a new window Called diff, showing you the contents of you file.

This is of course not ideal as the diff window will have the diff colors polluting the text. Note: you can compare the file you want to open to and empty file, and then you will have the window in a very ugly green background.

This is not perfect, it is a hack, but it was the only way I found to really have the same file in two windows.

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As the question is too old, do not know answering this is like beating a dead horse to run or not. But if someone is using VSCode 1.62.1 or later, to see the same script in another tab just simply right click on the script name on the toolbar and select "split right" (or split up/down/left).

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