All table based output targets (HTML, Execl, Layouted CSV) have some layout restrictions. These layout restrictions also apply to the PlainText output target:

The elements must be aligned properly, they must not overlap. When overlapping, the left element gets preferred over the right element, and top elements have a higher preferrence level as bottom elements.
The elements must be large enough to contain the element. This is important when specifying the cell/line height, the elements height must be greater than the minimum height. For Excel/Html cells the minimum height is equal to the font height, so you'll just have to make sure that the cell is able to print at least one line of text.
For PlainText, the line height is defined by the LPI setting, if LPI (lines per inch) is set to 10, then the minimum height of a line should be 72/10 points, so specifying a element height of 8 is safe. If LPI is set to 6, then the line height should be at least 72/6, so a element height of 12 should be ok.
The Epson- and IBM plain text output does not handle 16-bit character sets. When using the PlainText output target to send the output to an printer, make sure that your printer is able to handle the used text encoding.
When specifying colors for the Excel target, then these colors are translated into one of the predefined excel color constants. This translation tries to find the nearest color, if that fails, the colors could look weird. Using one of the predefined AWT colors is always safe, everything else should work, but there are no guarantees.

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