Joe, Thanks for your rapid and very helpful reply which links the problem to MathML (?) and a Maple 2D Math Input operator. I have not been able to generate your ...,none(),none(),... expression with "Convert To > Inert Form". I do reproduce it with "Convert To > Atomic Identifier" which as you found does not display the overarrow. The first expression you provided does what I want. I am not sure if your expression is valid MathML. It appears to be a MapleSoft 2D Math Input operator (distinct from MathML?). I tried exporting from the palettes in Design Science's MathType 5.2c. I use their palettes to create the symbolic expression. Set their Preferences > Translators > Translation to other language (text) > MathML 2.0. Then copy the MathType symbols to the clipboard and paste into Maple. Maple presents a dialog box that gives you the option of converting MathML to 2D Math. The result is the same indexed expression that Maple creates using its own palettes (my 2nd Example) which is not what I want. I wonder if there is another math writer (http://www.w3.org/Math/) that has the flexibility to generate MathML that Maple would translate to the desired 2D Math Input? In any case your solution works and I hope this issue will be addressed by MapleSoft. I will create a tech support issue on it.

Further searching turns up earlier vitriol on related matters: http://www.mapleprimes.com/blog/pchin/avoiding-evaluation-with-2-d-math It appears that some people make a distinction between MathML and mathml. At a minimum, the former is different from 2D Math Input. However nothing I do with the following stuff resolves the palette issue I identified: Tools > Options > Display > Typesetting level: Extended View > Typsetting Rules ...

Maple 11 on Windows XP Pro. Example: Select subliteral from Layout Palette, type "V", type "tab", type "x". Highlight the entire entry and select RightOverArrow from Accents palette, type "Enter". You get the error message. Example: Select RightOverArrow from Accents palette, type "V", type underscore ("Shift" "-") to enter subscript, type "x", type "Enter" . lprint(%) to see "x" as an index [x] rather than incorporated as a subliteral.