[Bug] Shift+Click thumbnails degraded behavior in 10.6

[Hobatron]

WebViewer version
10.6
The current behavior
Shift clicking thumbnails only let's you select one set of documents this is a degraded behavior from previous versions.

The expected behavior
In past versions you could shift+click a set of docuemnt, then shift+click others separate from the first. This is a behavior our customers REQUIRE, and we've had to make a local version to fix this lost functionality.

Steps to reproduce
Use shift+click a set of documents, then try and shift+click another set. You lose your first set of selected documents.

This seems fairly intentional, but we can't understand why.

FIX:
https://github.com/PDFTron/webviewer-ui/blob/3b0baead7c2fda7d7d1661b2e092fda74eba1a67/src/components/Thumbnail/Thumbnail.js#L180

Add: ...updatedSelectedPages,

[bollain]

HI @Hobatron,

Thanks for reaching out.

This behaviour is still supported - for the second selection you must use the CTRL key. We changed this behaviour as the previous code was creating unintended side effects.

Screen.Recording.2024-01-30.at.6.10.31.PM.mov

[bollain]

Looking at this code again, this issue may have been due to the pivot index. This was the issue we came up against that caused this change:
Open the thumbnails panel.
Select Page 1, and then click shift to page 4
1-4 will be selected
Now de-select page 2 then 1, in this order
Now select page 2 with click + shift
1-4 will be selected, when we wanted 2

271157114-b8679851-d216-43ed-896d-159e842ac600.mov