Deferring panel updates is a tedious procedure, requiring a panel reference (not intuitive to get!) and a couple of property nodes. However, deferring panel updates is sometimes very important. For example when coloring the fields of a large table according to their values, a serious performance impact is encountered unless we defer panel updates. There are many other situations where panel updates should be suspended temporarily, especially if property nodes are used in a tight loop.
My suggestions is to make flat sequences a little bit more useful by adding a new function to the right-click menu of each frame: "Defer Panel Updates". Now a new connector will appear on the frame that accepts a panel reference. If left unwired, this applies to the panel of the current VI, but we can wire a reference to any panel we desire (useful for subVIs). There should be a visual indication indicating that updates are deferred, e.g. a slightly different background pattern (e.g. faint checkerboard or similar). Note that this idea does not clutter the palettes with a new structure, but simply extends the functionality of existing elements. Let's put those sequences to some good use!
During execution of such a frame, the panel updates are deferred and automatically enabled again once the frame ends. The configuration should be "per frame" of a multi-frame flat sequence.
This has many advantages over the current situation:
It is immediately clear what part of the code executes during the deferral
The deferral is clearly delimited and it is not possible to accidentally forget to re-enable the updates
As an example, here is my subVI code to color the fields of a large correlation matrix (located on the main VI) according the respective value so we can easily pick out where correlations between fitting parameters are a problem.
TOP: current solution. BOTTOM: how it could look like with this idea implemented.