Selection in Frozen columns + selectable: "multiple cell" scenario does not work as expected

[kendo-bot]

Bug report

Selecting cells from the frozen table in Frozen columns + selectable: "multiple cell" scenario selects the bellow cells from the non-frozen table

Reproduction of the problem

Open below Dojo

https://dojo.telerik.com/exobAcEl

Scroll the horizontal scrollbar to the right.

Select some cells from the frozen table.

Move the scroller back to its original position.

Expected/desired behavior

Cells from the non-frozen table shall not be selected.

EnvironmentKendo UI version: [all]
Browser: all

[gyankov]

Currently the Selectable widget determines which element is selected using the coordinates of the of the selected area. Every element which is under the selected area is marked as selected. Thus, in this case, when you scroll right, the first non locked column appears below the second locked column and upon selection, both are selected.

If we fix the current behavior, we will introduce the following issue:

When you want to select all cells, all cells which are not visible due to the scroll will remain unselected:

I've discussed this with @nedevp and we believe that the behavior after the fix might cause more confusion.

What do you guys think @VicTachev @ag-petrov? Are we okay to omit selecting the non visible cells with range selection or we should keep the behavior as it is now?

[VicTachev]

Indeed, altering the default behavior can also produce unexpected results.
Is there an example we can show in a KB that shows how Selectable behavior can be changed? That will enable changing how Selectable works based on the specific scenario it is used in.

[gyankov]

After a discussion with @ag-petrov and @VicTachev we decided to introduce a setting which will prevent selection of overlapped elements.

selectable: {
    ignoreOverlapped: true
}

When the above setting is set to true, only elements with a visible part covered by the marquee will be selected.

[dmanova]

Notes from internal testing

• Indeed there are some columns that are selected, but should not as they overlapped. Here is the runnable sample (need to replace refferences) where reproducible https://dojo.telerik.com/inEtEloJ . And here rare some videos on the selection:

• Also in RTL mode the column that is partially under the frozen columns is not selected - https://dojo.telerik.com/inEtEloJ/2

• The following related issue should be consider when using sticky columns: Selected sticky columns are missing some styling in multiple cell selection #6294