**BUG** Concise problem statement: If a sim has run OK and then a change is made to the circuit that stops the next sim running then when the user runs the next sim, WaveForm shows the plots from the last sim but with no warning that a new sim has not been run. It is only if the user remembers to open the Simulation Results window that they see a warning. Steps to reproduce bug: 1. Open: https://easyeda.com/file_view_Wallman-2_l31nJG20m.htm 2. Ctrl+R 3. Edit Q1 or Q2 from 2N3904 to PN2222A 4. Save then Ctrl+R 5. After WaveForm window opens, go back to schematic and do: `Simulate > Simulation Results...` then read the Simulation Report. Results: **************************************** Circuit: wallman 2 Error on line 13 : q2 q2_1 r5_1 q1_1 pn2222a Unable to find definition of model ngspice stopped due to error, no simulation run! errors/warnings in your design, please fix them if you need. Doing analysis at TEMP = 27.000000 and TNOM = 27.000000 Warning: v1: no DC value, transient time 0 value used Initial Transient Solution -------------------------- Node Voltage ---- ------- r1_1 15 in 0 out 0 re_1 1.80895 c6_1 1.45425 q2_1 11.5159 r5_1 4.75926 r2_1 2.45243 q1_1 3.97069 pn2222a 11.5159 v1#branch 0 v2#branch -0.00196994 No. of Data Rows : 1008 ngspice-26 done **************************************** Expected results: Need to warn the user that the sim has not run. Do not show any plots (or warn that plots are from the last successful sim and not the last attempt?). Url: https://easyeda.com/file_view_Wallman-2_l31nJG20m.htm (but same problem can be seen in any sim). Browser:Mozilla/5.0 (Windows NT 5.1; rv:27.0) Gecko/20100101 Firefox/27.0