`R: Open help for selection` fails for some functions

Describe the bug

r.helpPanel.openForSelection (R: Open help for selection) sometimes fail to work although documentation-on-hovering does.

See the example below where I cannot use the command to open the documentation for glmnet::glmnet(), although the documentation shows when hovering (via the language server), and also opens up correctly when I execute ?glmnet. This also happens for instance with the function bag() from the caret package, so this is not a problem only with functions named exactly as the package. For the built-in function lm() and also for other functions such as ggplo2::geom_point() the command works fine.

To Reproduce Steps to reproduce the behavior:

1. Open an .R file.
2. Write the name of a function in the file.
3. Highlight the function name and select R: Open help for selection from the command tool box.
4. See error

Do you want to fix by self? (We hope your help!)

Yes, I’ll take a look at it.

setting.json:

{
    "r.rterm.linux": <path-to-radian>,
    "r.sessionWatcher": true,
    "r.rmarkdown.codeLensCommands": [
        "r.runCurrentChunk",
        "r.runAboveChunks",
        "r.runAllChunks"
    ],
    "r.bracketedPaste": true
}

Expected behavior

I expected the documentation to open up.

Environment (please complete the following information):

• OS: Linux
• VSCode Version: 1.56.2
• R Version: 4.0.5
• vscode-R version: 1.6.8

[ManuelHentschel]

Does calling “Clear Cached Index Files & Restart Help Server” in the R sidebar do anything?

[ManuelHentschel]

Glad to hear this worked. If you frequently run into this issue, you can set "r.helpPanel.cacheIndexFiles": "None" (we could also use this as default to avoid confusion, not sure how the performance of the the help viewer is for other users).

As a side note, usually you don’t need to select the entire word you want to look up, having the cursor inside the word should be enough.