Years ago I used Ideas cad software, and in that software sketches tended to blow up if you made changes to the history tree. In Solidworks, I was pleased that sketches tended to be more stable. NO MORE! If you change a sketch plane, it's likely that the sketch will blow up. If you even change the direction of an extrude, the sketch may blow up! I will attach a photo of a sketch that blew up just because the direction of the extrude was changed. ALSO, when you attempt to fix one of these sketches, weird things happen, like lines try to snap far away from where you may try to end them, and other odd behavior.
SO, here's another step backwards in this software. Now we have half colored and half blue icons, and sketches that blow up.
Hi James,
I have not experienced this on 2016. If the sketch plane changes I would expect that some of the sketch constraint to dangle or become over define (i.e. by the very nature that the circle is no long concentric to the external reference); looks like your sketch plane in your pic is not normal to the intended geometry anymore? I use both SW and CREO and the same thing happens in CREO as it does SW. However, don't loose hope, with a little care and intelligence on the part of the user, dangling/overconstrained sketches can be resolved. If you find that deleting certain constraints move sketch unpredictability, then fix all your sketch geometry first, then delete all constraints at once (using the property manager) and you should be able to re-apply constraints. This is only one way to do it, there are other ways and it depends on what you have sketched.
Mark