Select two rows whenever

When using MergeCells, we want to select two rows or more rows with goRowSizing in Options.

We shouldn't select cells like this Image. Please tell me how to solve this.

I cannot see the image here and your question is not really clear to me.
When a cell is merged, it is considered as one cell, so separate selection of subcells is not longer (visibly) possible.

I'm sorry I can not convey it well.

For a grid that is vertically merged, even if you select a row, not all the columns, including the merged row, will be selected.

Please tell me how to choose.

I cannot see a problem here. The grid behaves as expected.

Test:

I want to avoid uneven selection like this image and select cells flatly.

In this case, I want to select two rows which is not merged and a row which is merged whenever I select rows.
In other words,Can I select rows by height of the most big cell in rows?

When there are not merged columns, for a single row selection, only a single row will be selected. This is by design. If you want everything to be selected, you'd have to merge the cells in the other columns too.