Enablement using listDoubleSelection and listMultiSelection not working in contributed view

[aeisenberg]

Issue Type: Bug

I am creating an extension with a custom view. I am trying to make sure that certain commands are only enabled when there are two items selected and other commands when only a single item is selected.

I have tried using "enablement": "listDoubleSelection" and "enablement": "!listMultiSelection" in the command declaration for these cases. However, it looks like the values listMultiSelection and listDoubleSelection are always false.

Perhaps I'm doing something wrong, but I'm pretty sure I'm following the docs.

I'm attaching a zip of a sample project that illustrates the problem I'm having.

multi-select-bug.zip

To reproduce:

1. unzip the workspace above
2. open workspace in vscode
3. run the extension
4. open the view with the icon like this:
5. select one or multiple items in the list view and right click. Notice that the enablement of the commands does not follow what is in the package.json file.

VS Code version: Code 1.45.1 (5763d90, 2020-05-14T08:33:47.663Z)
OS version: Darwin x64 19.5.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz (16 x 2400)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: disabled_off protected_video_decode: unavailable_off rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled viz_display_compositor: enabled_on viz_hit_test_surface_layer: disabled_off_ok webgl: enabled webgl2: enabled
Load (avg)	2, 3, 3
Memory (System)	64.00GB (34.46GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions (22)

Extension	Author (truncated)	Version
vscode-markdownlint	Dav	0.36.0
vscode-eslint	dba	2.1.5
gitlens	eam	10.2.1
tsl-problem-matcher	eam	0.2.0
vscode-html-css	ecm	0.2.3
prettier-vscode	esb	5.0.0
vscode-diff	fab	1.4.0
wolfram-language	fli	0.1.0
vscode-codeql	Git	1.2.2
vscode-pull-request-github	Git	0.16.0
vscode-test-explorer	hbe	2.19.1
mysql-syntax	jak	1.3.1
vscode-edit-csv	jan	0.2.9
code-beautifier	mic	2.3.3
vscode-docker	ms-	1.2.1
azure-account	ms-	0.8.11
vscode-typescript-tslint-plugin	ms-	1.2.3
vsliveshare	ms-	1.0.2274
debugger-for-chrome	msj	4.12.8
vscode-react-native	msj	0.16.0
vscode-zipexplorer	sle	0.3.1
html-css-class-completion	Zig	1.19.0

(1 theme extensions excluded)

[alexr00]

It looks like listDoubleSelection and listMultiSelection are not implemented for extension provided tree views. @joaomoreno, is this something you would consider adding at a lower level, or should I add this as a consumer of WorkbenchAsyncDataTree?

[joaomoreno]

They should 🤔 :

vscode/src/vs/platform/list/browser/listService.ts

Lines 867 to 868 in cadabab

	this.hasDoubleSelection = WorkbenchListDoubleSelection.bindTo(this.contextKeyService);
	this.hasMultiSelection = WorkbenchListMultiSelection.bindTo(this.contextKeyService);

Must be a bug in some place. I would put my $$$ on which context key service the query is run on.

[joaomoreno]

@alexr00 Where is that enablement value read, in our code base?

[alexr00]

I see it read here:

vscode/src/vs/workbench/api/common/menusExtensionPoint.ts

Line 411 in 21e43b6

precondition: ContextKeyExpr.deserialize(enablement),

Then that precondition gets read in many places. Not sure which one is applicable here, but can do some digging.

[petrbroz]

This is probably related: I've been trying to achieve the same thing (showing/hiding specific commands in a custom tree view based on whether there are multiple items selected) by using listMultiSelection in the when clause, but with no luck.

If it is in fact possible to show/hide view/item/context items based on the selection count, is that documented anywhere? Thanks!

[joaomoreno]

@alexr00 I would've made some $$$ here. 💸

[alexr00]

@joaomoreno indeed you would. Thanks for the context key service idea!