In the current versions of IRRICAD and FastQuote the only method to edit dimensions after placement is to explode and edit the constituents. However, it may be useful to control the display of dimensions separately from other items. What can you do if you have already drawn the dimensions and they are not on the layer you want?
Tips:
To change the layer select more than one dimension and use Change (instead of Change Type).
If you only have one dimension on the plan first draw a temporary line. Then select the line and the dimension and use Change to edit the layer. Now remove the temporary line.
Of course the layer can be set for the dimensions before they are drawn. (The default layer is controlled in Settings|Layers - Current Layers "Drawing").