I opened a Simulink model which is built in R2020a, it has a subsystem, and some parameters are given by the mask of this subsystem. It work well in R2020a, but I just cannot successfully change any value though the mask GUI, which means I put a new value in the box, and press the apply button, everything appears normal, but the value of mask are not actually changed. If I open the mask again, the value returns to the previous value. The only way I find in 2020b to do so, is get into the mask editing scheme, and value can be actually changed.