switch to show affected area for modules
When using blendif, I virtually always use the switch that highlights the affected parts of the image in yellow to adjust the effect.
With the addition of masks in dt, it would be useful to have a switch in each module that highlights the affected area of an image, taking into consideration masks as well as blendif.
This could even replace the highlight switch in blendif.
If a module's effect is restricted by masks, blendif or any future-feature, (e.g. if blendif or masks are enabled) show a switch in the header of the module that highlights the affected area of this module.