Thanks for providing the feedback as well as the screen shot. Unfortunately, I cannot reproduce your problem with the description and it's hard to align the video with the command line output. Could you send me a video with your actions and command line together to Hao.Fang@autodesk.com?
Happened to me again with Adaptive Degradation & Hardware Acceleration set to ON.
I try to Stretch a whole portion of piping in a block (Edit Block In Place) in Ortho mode by this method: clicking for base point to clicking for second point. Most of the time, when the Stretch preview flickers, the bug happens when I click for the second point. If I wait for the Stretch preview to complete its regen, then the click for the second point works. The piping block consist of a couple of complex Dynamic and Constrained Blocks that may contribute to the flickering of command's preview. I'm attaching the drawing. If you have a powerful computer/graphic card then create multiple copies of entities in the block (to try to slow the screen's graphic regen) and try to stretch the piping line by clicking a second point before the preview has time to regen. I removed a lot of stuff to reduce file size, so it may be a good idea that you insert any complex entities to make the file size around 5MB, if that can help for the bug.
Maybe the flickering is caused when working on a AutoCAD session with the drawing open for a couple of hours, resulting in a memory leak... I don't know. But the bug seems to happens to me when AutoCAD has "trouble" with making a quick regen of command previews. This is my observation on my side, so keep giving detailed info of your experiences as well
Edit: I closed the drawing and re-opened it, thinking it would reset memory, but the Stretch preview still flickers and the bug still happens. Now I downloaded and opened the file version on this post: It took a couple of Stretch commands but eventually the bug returned after 10 tries.
I didn't have any luck getting your file to do the same error - but I don't have a lot of time to look at it right now. The one constant right off the bat is the use of dynamic blocks...
I hope you may find something. There's so many factors that can influence bugs, it's hard to get to the source of the problem...
Happened again... Here's the video and command line copy / paste..
Command: m MOVE
Select objects: Specify opposite corner: 899 found
Select objects: r
Remove objects: Specify opposite corner: 5 found, 5 removed, 894 total
Specify base point or [Displacement] <Displacement>: cen of Specify second point or <use first point as displacement>: per to
>>Enter new value for ORTHOMODE <1>:
Resuming MOVE command.
It is still not ideal but I was able to workaround this issue by turning off dragmode. I got the idea from someone else mentioning that it occured more frequently while waiting for the object being moved to draw the preview for the new location. After turning dragmode off I no longer had any problems. Simply type "dragmode" into the command line and then type "off".
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