All,
I've updated the child app (raw code link here, or see above) to version 1.5. The biggest change is that the app now supports a new option you'll see when the "Dim" or "Brighten" action is selected for a button press: "Start dimming when button pressed, stop dimming when button is released."
Just as it sounds, this requires a button that supports "press" and "release" events, which includes a Pico using the Fast Pico driver (the app will check for this and not show this option if yours doesn't). It also requires bulbs/dimmers that support the startLevelChange and stopLevelChange commands (the app does not check for this at the moment). With this option checked, a button press will send a "start level change" command, and a button release will send a "stop level change" command. This is an alternative to using a simple press to step the level up/down by a set amount, which you can still do without this option. (EDIT: Later updates add support for a "held" event to do a startLevelChange and a release to do a stopLevelChange.)
Unfortunately for those with Hue Bridge bulbs used in Hubitat, there appears to be an issue with the "startLevelChange" and "stopLevelChange" commands in my testing. Specifically, either one immediately will change the bulb to "off" in Hubitat even though the bulb itself actually remains on. Because my dimming functions only work if the bulb is on (that's part of the reason I wrote this app), this may cause problems for some people. (EDIT: Later testing reveals that the startLevelChange and stopLevelChange commands still work even if Hubitat thinks the bulb has an incorrect switch state, so if you only use this style of dimming, you shouldn't be affected--only if you mix the two types of dimming, i.e., continuous and step up/down, and don't want long enough betweeen using them.)
This thread has more details on the problem I mentioned in the previous paragraph: Hue lights Start Level Change. However, as of the last post in that thread, staff did not seem able to replicate this problem. There may be renewed interest in the problem since more of us are noticing it now. If anyone uses Hue Bridge bulbs on Hubitat and wants to test, feel free. 
PS - I also changed my mind about "held" functionality. I have a Osram/Lightify two-button dimmer device, and I'll need to make use of "held" to get that device to work as intended--where I think most people would want to use a "press up" for on-type actions, a "hold up" for "start level change," and a "release up" for a "stop level change" (if dimming is configured this way; otherwise, just a step up on hold and nothing on release), then something similar but reversed for the bottom button with "off" being my recommendation for a press and some dimming actions for hold and (again optionally) release. Coming soon (EDIT: now released!).
