Modify Eclipse Project Explorer causing Issues after StartUp - eclipse

Question

I have an RCP Project. I currently want to modify the Project Explorer. I wrote an addition ContentProvider(implements ICommonContentProvider) and an additional LabelProvider (implements ICommonLabelProvider). In my plugin.xml I added the following:
<extension
id="navigator-viewbinding"
point="org.eclipse.ui.navigator.viewer">
<viewerContentBinding
viewerId="org.eclipse.ui.navigator.ProjectExplorer">
<includes>
<contentExtension
isRoot="true"
pattern="de.myapp.application.EditorResourceContent">
</contentExtension>
</includes>
</viewerContentBinding>
</extension>
And:
<extension
id="navigator-content"
point="org.eclipse.ui.navigator.navigatorContent">
<navigatorContent
activeByDefault="true"
contentProvider="de.myapp.application.ProjectExplorerContentProvider"
icon="icon.gif"
id="de.myapp.application.EditorResourceContent"
labelProvider="de.myapp.application.ProjectExplorerLabelProvider"
name="Editor Decoration"
priority="highest">
<triggerPoints>
<or>
<instanceof
value="org.eclipse.core.resources.IFile">
</instanceof>
<instanceof
value="org.eclipse.core.resources.IFolder">
</instanceof>
<instanceof
value="org.eclipse.jdt.internal.core.PackageFragment">
</instanceof>
<instanceof
value="org.eclipse.core.resources.IWorkspaceRoot" />
<instanceof
value="org.eclipse.core.resources.IProject" />
</or>
</triggerPoints>
<possibleChildren>
<or>
<instanceof
value="org.eclipse.core.resources.IWorkspaceRoot" />
<instanceof
value="org.eclipse.core.resources.IProject" />
<instanceof
value="org.eclipse.core.resources.IResource" />
<instanceof
value="org.eclipse.core.resources.IFolder" />
<instanceof
value="org.eclipse.core.resources.IFile" />
<instanceof
value="org.eclipse.jdt.internal.core.PackageFragment" />
</or>
</possibleChildren>
</navigatorContent>
</extension>
When I start the Editor, the Project Explorer won't show any projects, until I make a right mouse click. Then all projects are loaded. When I open the tree, I see no error markers on my modified icons, but the icons themself are shown. Also I see the error markers on the packages(unmodified). I even see the egit decorators, but not the red markers for the errors.
Also I provide both of the Providers, maybe it will help give me some hints for both of my problems.
ContentProvider:
public class ProjectExplorerContentProvider implements
ICommonContentProvider
{
private static final Object[] NO_CHILDREN = {};
#Override
public Object[] getElements(Object inputElement) {
return getChildren(inputElement);
}
#Override
public Object[] getChildren(Object parentElement) {
Object[] children = null;
if(IWorkspaceRoot.class.isInstance(parentElement))
{
IProject[] projects = ((IWorkspaceRoot)parentElement).getProjects();
children = createParents(projects);
}
else
{
children = NO_CHILDREN;
}
return children;
}
private Object[] createParents(IProject[] projects)
{
Object[] result;
List<Object> list = new ArrayList<Object>();
for (int i = 0; i < projects.length; i++) {
try {
if(projects[i].hasNature("org.eclipse.xtext.ui.shared.xtextNature"))
list.add(projects[i]);
} catch (CoreException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
result = new Object[list.size()];
list.toArray(result);
return result;
}
#Override
public Object getParent(Object element) {
Object parent = null;
if(IProject.class.isInstance(element))
{
parent = ((IProject)element).getWorkspace().getRoot();
}
return parent;
}
#Override
public boolean hasChildren(Object element) {
boolean hasChildren = false;
if(IWorkspaceRoot.class.isInstance(element))
{
hasChildren = ((IWorkspaceRoot)element).getProjects().length > 0;
}
return hasChildren;
}
#Override
public void restoreState(IMemento aMemento) {
}
#Override
public void saveState(IMemento aMemento) {
}
#Override
public void init(ICommonContentExtensionSite aConfig) {
}
}
And here the LabelProvider:
public class ProjectExplorerLabelProvider implements ICommonLabelProvider{
/****/
#Override
public void addListener(ILabelProviderListener listener) {
// TODO Auto-generated method stub
}
#Override
public void dispose() {
// TODO Auto-generated method stub
}
#Override
public boolean isLabelProperty(Object element, String property) {
// TODO Auto-generated method stub
return false;
}
#Override
public void removeListener(ILabelProviderListener listener) {
// TODO Auto-generated method stub
}
#Override
public Image getImage(Object anElement) {
if (anElement instanceof File) {
File fi = (File) anElement;
if (fi.getFileExtension().equalsIgnoreCase("mydsl")) {
return Activator.getImage("icons/img1.png");
} else {
try {
InputStream inputStream = fi.getContents();
String content =
ContentFactory.getInstance().toStringInputStream(inputStream);
inputStream.close();
if (content.contains("some string")) {
return Activator.getImage("icons/img2.png");
} else if (content.contains("some other string")) {
return Activator.getImage("icons/img3.png");
} else if (content.contains("some other string")) {
return Activator.getImage("icons/img4.png");
}
} catch (CoreException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
} else if (anElement instanceof Folder) {
Folder fo = (Folder) anElement;
}
else if (anElement instanceof PackageFragment) {
PackageFragment pf = (PackageFragment) anElement;
}
}
return null;
}
#Override
public String getText(Object element) {
// TODO Auto-generated method stub
return null;
}
#Override
public void restoreState(IMemento aMemento) {
// TODO Auto-generated method stub
}
#Override
public void saveState(IMemento aMemento) {
// TODO Auto-generated method stub
}
#Override
public String getDescription(Object anElement) {
// TODO Auto-generated method stub
return null;
}
#Override
public void init(ICommonContentExtensionSite aConfig) {
}
}

Answer 1

When I start the Editor, the Project Explorer won't show any projects,
until I make a right mouse click. Then all projects are loaded.
For this problem you can try this:
Update 2015-08-24: if in the final application the ProjectExplorer
content is not visible by its own (but only after you forced an
updated, e.g., via opening the context menu with a right-click), try
this: override the getDefaultPageInput() method of the
ApplicationWorkbenchAdvisor and add the following line:
return ResourcesPlugin.getWorkspace().getRoot();
Source:
https://dirksmetric.wordpress.com/2012/08/01/tutorial-eclipse-rcp-e4-with-3-x-views-like-project-explorer-properties-etc/
When I open the tree, I see no error markers on my modified icons, but
the icons themself are shown.
I think you override the Icons with the decoration? So its clear that there are no decoration on it.