The Instant Preview Mode (IP) is disabled when selecting a Filter brush with Gaussian effect (for example).  The check box in the panel goes dark with strike-thru text. Thereafter, selecting another brush does not necessarily reset the mode.  It stays disabled for all brushes.  Only tickling a parameter, like Size or Ratio in the Pixel brush for instance,  resets, it.  Not all parameters do this though.

Also, assuming the IP Mode menu item should always reflect the Brush engine panel setting (and vice-versa), it doesn’t. The menu item stays checked even though the brush engine settings say its off.

Finally, with IP Mode OFF (via menu), shouldn’t it be disabled for all brushes? No matter what brush setting is changed?

NOTE: My understanding of how IP mode works may be twisted.  Please advise if that's the case, but I didn't find the current workflow intuitive.


Reproducible: Always

Steps to Reproduce:
1. Just to be safe, cleared all of my krita settings
2. Open krita with a new document
3. Set Instant Preview (IP) Mode On (via menu)
3. Click the toolbar Brush Settings icon - IP is, by default, checked.
4. Cycle through some other brush engines to verify that IP is enabled/checked everywhere
5. Select Filter and IP is disabled (goes dark after a split second)
6. All other brush settings now have IP disabled
7. Select another brush and IP is re-enabled ONLY after selecting the right parameter (for Pixel, Size or Ratio does thr trick)



Expected Results:  
1. When switching to a non Filter brush, IP mode should be (re)enabled if its compatible 
2. The IP Mode menu setting should always reflect the current brush engine setting