Whenever you close the Equation Editor, Vensim will try to make sense of what you have entered. If the model has problems, these will be marked, and whatever causal structure can be interpreted will be interpreted. In this manner it is always possible to do causal tracing, though for incompletely-defined subscripted variables the accuracy of the causal tracing can be limited.
When you use the Equation Editor to make a change to the structure of the model Vensim will check to be sure that the sketch information for the model is also updated. If, for example you remove a feedback link, Vensim will remove that feedback link in any views it may have appeared. When you close the Equation Editor the Sketch Editor will sometimes flash because of this updating. This can happen independent of whether you launch the Equation Editor with a Sketch tool or by clicking on an Equation Editor tool on the Analysis toolset.
