Try this. It selects both, not and partially associated dims.
(defun c:SelDimUnAssociated ( / isDimAssoc? m s i e)
; by Vl. Michl CADStudio
; returns nil or assoc point number
(defun isDimAssoc? (diment / elst dict)
(and (setq elst (entget diment))
(setq dict (cdr (assoc 360 elst)))
(setq elst (entget dict))
(setq elst (entget (cdr (assoc 360 elst)))))
(cdr (assoc 90 elst)))
; ------------------------------------------------------
(princ "\nSelect dims to analyze associativity ... ")
(setq m (ssget "_I" '((0 . "DIMENSION"))))
(if (setq s (ssget '((0 . "DIMENSION"))))
(repeat (setq i (sslength s))
(setq e (ssname s (setq i (1- i))))
(if (= (isDimAssoc? e)
(cadr (assoc (cdr (assoc 100 (reverse (entget e))))
'(("AcDbAlignedDimension" 3)
("AcDbRotatedDimension" 3)
("AcDbRadialDimension" 2)
("AcDbDiametricDimension" 2)
("AcDb3PointAngularDimension" 7)
("AcDb2LineAngularDimension" 15)
("AcDbOrdinateDimension" 2)
("AcDbRadialDimensionLarge" 2)
("AcDbArcDimension" 7)
))))
(ssdel e s))))
(if m (sssetfirst nil nil))
(if (and s (not (zerop (sslength s))))
(sssetfirst nil s))
(princ)
)