ADF 12c Rendering Problems at design time

Question

Hi all,
I am experimenting the following unexpected rendering problems at Design time with JDEV 12c:
-  Sometimes a complete page is showed empty or blank but the components exists on the page (you can see them in the structure panel) and the page has no warnings.
-  Sometimes I cannot click a component because it is behind the container.
-  Sometimes the containers are rendered in other place on the page.
-  Sometimes the containers not stretching
I remember some posts about this problem in 11.1.2.x but I think it was not fixed in 12c. For this reason, I have some questions:
What is the "real" memory requirement  of Jdev 12c to avoid render problems?
What is the best configuration in jdev.conf?
Is it only a memory issue or Is it also a dependency reference problem? According to a blog post of Frank Nimphius:
Though with Oracle JDeveloper 11g the problem of the IDE not rendering JSF pages properly in the visual editor has become rare, there always is a way for the creative to break IDE functionality. A possible reason for the visual editor in JDeveloper to break is a failed dependency reference, which often is in a custom JSF PhaseListener configured in the faces-config.xml file. To avoid this from happening, surround the code in your PhaseListener class with the following statement (for example in the afterPhase method)
public void afterPhase(PhaseEvent phaseEvent) {   if(!ADFContext.getCurrent().isDesigntime()){ ... listener code here ... } }
The reason why the visual editor in Oracle JDeveloper fails rendering the WYSIWYG view has to do with how the live preview is created. To produce the visual display of a view, JDeveloper actually runs the ADF Faces view in JSF, which then also invokes defined PhaseListeners. With the code above, you check whether the PhaseListener code is executed at runtime or design time.If it is executed in design time, you ignore all calls to external resources that are not available at design time.
source:
https://blogs.oracle.com/jdevotnharvest/entry/when_jdeveloper_ide_doesn_t
if it is a known problem, then Why is not fixed in 12c?
Jhon
Jdev 12c

Answer 1

Jhon, what Frank mentioned can't be fixed from the outside. You or the developers who use phase listens without thinking about the design view are the ones to fix this. Frank provided you with the solution for this.
However, we don't know if you use any self written phase listener. If you don't do this you have another problem. I do see some of your symptoms but can't reproduce them at the moment. As long as we can't reproduce the problem somehow it's difficult to to get a solution.
My advise is to keep your eyes open (add I do) and whenever you can reproduce this behaviour come back and tell us about it. It's hard or impossible to give the 'best' settings for Jdev.conf as they depend on other factors e.g. operating system, memory, other applications running at the same time and many more.
Personally I don't change the parameters as long as I can't put the problems to low memory (which I can't at the moment).
Timo