SOLVED: Problem with selecting thousands of objects in DRAW X5 W7-64

I am working with floor plans that probably originated in AutoCAD, that I imported into DRAW X5 (15.2.0.695) from PDF. As is typical, there are thousands of hairline curves, almost all as outline segments. In this particular plan there are 13,316. There are no bitmaps and no text. File size is 1,238 KB.

The M6500, as can be seen from my signature description, is a machine that is made for this kind of stuff. It runs the Suite great; starts up in under 2 seconds. However, when I attempt to select all objects in the file mentioned above, it appears to select objects one-by-one rapidly through all the objects for about 4 seconds, then start over again. It continues through this "loop" without ever stopping and making a selection. I seem to be able to successfully select around 8k objects.

What's odd is that the two XP machines make a selection of all objects almost instantly. The M70 struggles transforming the selection, but hey, it's almost 10 years old! I'm rather astounded that the Optiplex 780, being just a general office computer, handles darn near anything I throw at it and it handles this file without sweating. 

I have done much searching to no avail with this issue. Any guidance would be greatly appreciated!