This tests shift + selecting two discontinuous elements with user-select: all. WebKit should select the both elements instead of moving the selection.
To manually test, click to select the first element and shift-click the second element. WebKit should select both elements.

After clicking on the first element (Mac):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "<#selection-anchor>First element<#selection-focus>"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "Second element"
| "
"

After shift clicking on the second element (Mac):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "<#selection-anchor>First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "Second element<#selection-focus>"
| "
"

After clicking on the second element (Mac):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "<#selection-anchor>Second element<#selection-focus>"
| "
"

After shift clicking on the first element (Mac):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "<#selection-focus>First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "Second element<#selection-anchor>"
| "
"

After clicking on the first element (Win):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "<#selection-focus>First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "Second element<#selection-anchor>"
| "
"

After shift clicking on the second element (Win):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "<#selection-focus>Second element<#selection-anchor>"
| "
"

After clicking on the second element (Win):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "<#selection-anchor>Second element<#selection-focus>"
| "
"

After shift clicking on the first element (Win):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "<#selection-focus>First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "Second<#selection-anchor> element"
| "
"

After clicking on the first element (Unix):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "<#selection-focus>First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "Second<#selection-anchor> element"
| "
"

After shift clicking on the second element (Unix):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "<#selection-anchor>Second element<#selection-focus>"
| "
"

After clicking on the second element (Unix):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "<#selection-anchor>Second element<#selection-focus>"
| "
"

After shift clicking on the first element (Unix):
| "
"
| <div>
|   class="select-all"
|   id="first"
|   "<#selection-focus>First element"
| "
Some other text.
"
| <div>
|   class="select-all"
|   id="second"
|   "Second<#selection-anchor> element"
| "
"