PowerShell preview extension does not allow running selection from undefined files

[Glober777]

Issue Description

I've noticed that every time I create a new file (without saving it), set it as PowerShell, add in some code, select a fraction (or all of it), followed by pressing F8 I get a notification saying: Cannot read property 'name' of undefined:

Running selection with F8 starts to work only after I run the whole thing with first (F5).

This is not how it works in ISE.

Attached Logs

Couldn't find anything related in the logs. Please let me know if those are needed.

Environment Information

Visual Studio Code

Name	Version
Operating System	Windows_NT x64 10.0.17763
VSCode	1.37.0
PowerShell Extension Version	2019.5.0

PowerShell Information

Name	Value
PSVersion	5.1.17763.503
PSEdition	Desktop
PSCompatibleVersions	1.0 2.0 3.0 4.0 5.0 5.1.17763.503
BuildVersion	10.0.17763.503
CLRVersion	4.0.30319.42000
WSManStackVersion	3.0
PSRemotingProtocolVersion	2.3
SerializationVersion	1.1.0.1

Visual Studio Code Extensions

Visual Studio Code Extensions(Click to Expand)

Extension	Author	Version
azure-account	ms-vscode	0.8.4
azure-pipelines	ms-azure-devops	1.155.0
beautify	HookyQR	1.5.0
code-settings-sync	Shan	3.4.1
code-spell-checker	streetsidesoftware	1.7.17
csharp	ms-vscode	1.21.0
docs-article-templates	docsmsft	0.2.7
docs-authoring-pack	docsmsft	0.1.2
docs-markdown	docsmsft	0.2.13
docs-preview	docsmsft	0.3.25
docs-yaml	docsmsft	0.2.3
ecdc	mitchdenny	1.3.0
EditorConfig	EditorConfig	0.13.0
gc-excelviewer	GrapeCity	2.1.32
gitlens	eamodio	9.9.3
live-html-previewer	hdg	0.3.0
mssql	ms-mssql	1.6.0
partial-diff	ryu1kn	1.4.0
pomodoro-code	odonno	0.2.1
powershell-preview	ms-vscode	2019.5.0
team	ms-vsts	1.149.2
theme-hackershaze	Nuuf	2.0.1
todo-tree	Gruntfuggly	0.0.141
vscode-hexdump	slevesque	1.7.2
vscode-logicapps	ms-azuretools	0.2.9
vscode-markdownlint	DavidAnson	0.30.1
vscode-yaml	redhat	0.4.1
xml	DotJoshJohnson	2.5.0

[SydneyhSmith]

@Glober777 thanks for opening this issue, we were able to re-produce this and it looks like it is occurring because it looks as if vscode.window.activeTerminal is undefined until you have clicked into the terminal.

FYI @Tyriar not sure if you guys are aware/expecting this behavior, it doesnt seem ideal considering the terminal is in view/appears active

See the above PR for the workaround.

[Tyriar]

This is by design, a terminal only becomes active once it is first focused.