Issues with row and column spans in grid

I have been using the dhtmlxgrid for displaying tables, and have run into some issues concerning rowspans and colspans. I have seen some weird behavior where colspans and rowspans are sometimes not rendered correctly. For example, I have a four column table with a colspan. The colspan runs across two colunms (comprising the first two columns). The XML configuration looks like this:

<row>
    <cell colspan="2">Columns 1 and 2</cell>
    <cell>Column 3</cell>
    <cell>Column 4</cell>
</row>

This configuration results in a row where “Columns 1 and 2” spans the first two columns and “Column 4” is displayed in the third column. The words “Column 3” is not displayed. Not sure why this happens. Any suggestions?

Another concern of mine related to the row and column spans is the ability to have a column span and row span in the same cell. I have seen statements throughout the site that suggest that this is not possible. Can anyone confirm this?

You should use:

Columns 1 and 2 Column 3 Column 4

Another concern of mine related to the row and column spans is the ability to have a column span and row span in the same cell.
No, it not possible to have row and col span at the one cell.

Olga, thank you for your response.

I just want to be sure that I was clear on my question about whether or not a colspan and rowspan may appear in the same cell. Consider the following example:

<row>
  <cell rowspan="2" colspan="2"></cell>
   ...
</row>

This is what I mean by rowspan and colspan appearing in the same cell. My question is: is this valid?

Thank you in advance!

My question is: is this valid?
No, it’s not valid. It not possible to use rowspan and colspan at one cell.