Using keyboard shortcut 'h' with PDF changes pointer to Hand Tool

[mattdricker]

Reported by user: https://app.hubspot.com/contacts/6291320/ticket/405369758/

Describe the bug
When annotating a PDF, using the keyboard shortcut 'h' to create a highlight changes the pointer from the Text Selection Tool to the Hand Tool. This forces the user to manually change the pointer back to the Text Selection Tool to continue highlighting or annotating.

This only occurs using keyboard shortcut 'h'. Using 'a' does not alter the Text Selection Tool.

Note: This is most likely due to PDF.js also using the 'h' key for selecting the Hand Tool. The 's' key selects the Text Selection Tool.

To Reproduce
Steps to reproduce the behavior:

1. Open a PDF in browser
2. Activate Hypothesis extension or bookmarklet
3. Select text, and type 'h' to create a highlight
4. Note that the pointer tool changed from Text Selection to Hand Tool

Expected behavior
User should expect that the Text Selection Tool would remain unchanged after using 'h' to highlight.

Confirmed in Chrome 90 & Firefox 88, MacOS 11.3.1

[mattdricker]

Here's a list of built-in PDF.js keyboard shortcuts: https://github.com/mozilla/pdf.js/wiki/Frequently-Asked-Questions#faq-shortcuts

[robertknight]

It might be OK to use the same shortcut that PDF.js uses for another purpose because it only applies when there is a text selection. We'd need to make sure that the default PDF.js shortcut is not invoked in that case.

It would be good to consider the alternatives as well.

[mkdir-washington-edu]

Referenced here: hypothesis/product-backlog#1202