Can't edit, delete, or move objects in a drawing

Hello,

I am new to AutoCAD this year, just started an internship for the summer that uses it heavily. I am using AutoCAD P&ID 2015 while the drawings I am receiving are from a user who has 2007 or 2010 classic (NOT P&ID). The problem I am having is almost exactly the same as this post: http://www.cadtutor.net/forum/archive/index.php/t-2531.html

However my drawing does not contain a layer with xref in the name.

I am trying to select some line segments and either move or delete them but it will not let me. Most of the lines in the drawing can be selected, moved, deleted, but some cannot. When I click the lines that can't move it does not display the grips but it does become a dashed line, like its partially selected or something.

idk if the history of this drawing matters but it was orginally created on a P&ID version of AutoCAD and exported so it could be opened and edited by others with an AutoCAD classic version. After all of this it was sent back to me, which I am editing this drawing now with the workspace set to Drafting & Annotation.

Let me know if I have not provided sufficient information needed to solve this problem. I would really appreciate any inputs or suggestions you may have.

Perhaps some layers are locked? Go to the layer manager and look for the little lock symbol to see if any are locked, if so pick on the lock once to toggle it to unlocked.

oh sorry, I forgot to mention that all layers were unlocked.

I actually had that in there on my first attempt to post that but my browser crashed and had to retype

Open the Properties Palette and select one of the problem objects. What type of object is it? Line, Polyline, AEC_xxx, Proxy Entity, etc

what are the type of objects you are selecting, click the drop down arrow in the properties palette

EDIT: Like what Nestly said first

it appears that all the problem objects are either SLINE and ACPPASSET

I'm not familiar with AutoCAD P&ID but my guess is that Schematic Lines and/or ACPPASSETs are dependent on other objects which is why you can't edited them singularly. I'm not sure how many P&ID users we have here, but you might also try asking over at the Autodesk AutoCAD P&ID forums.