Do the rows of a matrix have any symbols of continuity between rows of a matrix?

Sorry, I don't understand what you mean. Mrow={{1,2,3},{4,5,6},{7,8,9}} defines a 3x3 matrix. Where or how did you use '...' or "+" in scripting and what do you mean by 'creating the rows manually'?

You can define separate lists l1, l2 and l3 and define m={l1,l2,l3} if this can help you

Nevertheless I'm still wondering about the 'problem'. First a definition m={{1,2,3}, ...} is not a typical scripting syntax but a 'normal' definition. Second what's the problem about a limited scripting window and in which version? If you're talking about the scripting tab of a button, you can just keep on typing. The definition just appears on different lines but that doesn't cause any problem for the definition itself in situations like following in which I just kept on typing, not bothering about separating lines:

The command has to be on a single line. This works fine:

Lcolor = {{85,85,0},{85,170,0},{85,255,0},{170,85,0},{170,170,0},{170,255,0},{255,85,0},{255,170,0},{255,255,0},{0,85,128},{0,170,128},{0,255,128},{85,0,128},{85,85,128},{85,170,128},{85,255,128},{170,0,128},{170,85,128},{170,170,128},{170,255,128},{255,0,128},{255,85,128},{255,170,128},{255,255,128},{0,85,255},{0,170,255},{0,255,255},{85,0,255},{85,85,255},{85,170,255},{85,255,255},{170,0,255},{170,85,255},{170,170,255},{170,255,255},{255,0,255},{255,85,255},{255,170,255},{43,0,0},{85,0,0},{128,0,0},{170,0,0},{212,0,0},{255,0,0},{0,43,0},{0,85,0},{0,128,0},{0,170,0},{0,212,0},{0,255,0},{0,0,43},{0,0,85},{0,0,128},{0,0,170},{0,0,212},{0,0,255},{0,0,0},{36,36,36},{73,73,73},{109,109,109},{146,146,146},{182,182,182},{219,219,219},{255,255,255}}

as Mike said put in a button it works the same way as a normal input. So what you didn't show in your screenshots is that one way or another you did use line ends in your input instead of just keep on typing as I wrote before

A possibility in the attachment (using TextTool and Execute())

(obviously the line breaks in the text within Execute are not taken into account, I suspect that this (reasonable) behavior is not necessarily guaranteed in future releases)