TRIM ANOMALIES - HELP!

[IdeaLogic584307]

I often use the TRIM command to remove extraneous portions of one entity in order to join that entity to a second entity (the second acting as the trim boundary), in order to form a continuous polyline (using PEDIT and JOIN). But, unless the entity is trimmed completely up to the boundary, the join function will not be successful (i.e. the end points of the two entities must be coincident for JOIN to work). If an ellipse is involved, I set PELLIPSE to ‘1’ so that the resulting pseudo-ellipse segments can be JOINed to the polyline (i.e. true ellipse segments cannot be JOINed).

I recently switched from AutoCAD LT 2010 to LT 2015. Unless I’m mistaken, with LT 2010 when I selected an entity to TRIM and a boundary to trim to (even with a so-called pseudo-ellipse as the boundary), any and all portions of the entity beyond the trim boundary would be removed with a single mouse-click selection. But with LT 2015, depending on where I would click on the trimmed entity, sometimes only a portion would be removed, and an additional portion (between the removed portion and the boundary) would still remain.

Sometimes it would take several successive trims to completely remove the to-be-trimmed portion up to the trim boundary. Further complicating things, if a very small, not-visually-obvious portion still remains to be trimmed, the attempt to JOIN the entities fails. When this occurs, it requires ZOOMing in multiple times (especially with VIEWRES set low for fast regen’s) to the junction between the ‘trimmee’ and the ‘trimmer’ to TRIM off every last segment. Also, there are sometimes orphaned segments remaining past and/or between the successive trim points, requiring additional ERASEing.

In an attempt to analyze this, I set up four unique tests involving four entities (true ellipse, circle, line, 6-segment continuous polyline) as follows:

1. First, I created these four entities (see VIEW 1 of attached TRIM-TEST.DWG file).
2. Next, I copied the four entities to each of the two views on the left (TESTs 1 & 2 - true ellipses in green).
3. I then exploded only the polyline at the TEST 2 view (single polyline > six lines).
4. I then copied these two sets of entities to the right (TESTs 3 & 4), replacing the true ellipses with pseudo ellipses (i.e. PELLIPSE set to 1, ellipses redrawn in red with same major/minor axes, true ellipses ERASEd).
5. Finally, with the circle and ellipse as boundaries, I trimmed (one mouse click only at each trim point) the line and the polyline (or exploded polyline) in each of the four views (the attachment shows the final results of this TRIMming).

RESULTS:

TEST 1 (TRUE ELLIPSE, INTACT POLYLINE): POLYLINE and LINE – both complete trims
TEST 2 (TRUE ELLIPSE, EXPLODED POLYLINE): EXPLODED POLYLINE and LINE – both complete trims
TEST 3 (PSEUDO-ELLIPSE, INTACT POLYLINE): POLYLINE – complete trim, LINE – partial trim
TEST 4 (PSEUDO-ELLIPSE, EXPLODED POLYLINE): EXPLODED POLYLINE and LINE – both partial trims
Note: Partial trim points are marked with red X’s in TESTs 3 and 4 views.
OBSERVATIONS:

At first, I attributed this to trimming with a combination of an exploded polyline and a pseudo- ellipse, as in TEST 4. However, the partial trim of the line in TEST 3 suggest that’s not the definitive answer.
It seems that having both an exploded polyline and a pseudo-ellipse exacerbates the problem, but TEST 3 shows that it can also happen with just a pseudo-ellipse. And it can happen with just an exploded polyline as with the circle in TEST 4.

QUESTIONS:

Q1. Has anyone else noticed this behavior?

Q2. If so, do you have any tips to deal with it?

Q3. Is this considered a bug or a feature of LT 2015?

Q4. If there a workaround/setting to make TRIM remove the entire portion of the entity extending past the boundary with one mouse-click selection?