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JFace TableViewer - Deselected rows reselect themselves automatically, with bonus asynchronous weirdness

I'm writing an eclipse RCP program that has a single-select JFace TableViewer in the GUI. Single select TableViewers don't have a default way of deselecting the selection, so I figured I'd add one by adding my own listener. The idea is to clear the selection if the user clicks on the already-selected row.
myTableViewer.addPostSelectionChangedListener(new ISelectionChangedListener(){
private boolean inLoop = false;
private StructuredSelection previousSelection = StructuredSelection.EMPTY;
#Override
public void selectionChanged(SelectionChangedEvent event) {
//Needed because setting the selection causes the listener to be called again.
if (inLoop) {
inLoop = false;
return;
}
StructuredSelection newSelection = (StructuredSelection) event.getSelection();
if (newSelection.equals(previousSelection)) {
newSelection = StructuredSelection.EMPTY;
inLoop = true;
myTableViewer.setSelection(StructuredSelection.EMPTY);
}
previousSelection = newSelection;
}
});
This unfortunately doesn't work. The selection is very briefly cleared, but about .2 seconds later the TableViewer automatically reselects the row that I just barely deselected!
It gets better. I debugged the JFace code a little to try and solve the issue. The TableViewer delegates its selection code to a StructuredViewer. If I put a breakpoint in StructuredViewer.setSelection(...), then all of a sudden my code works.
Apparently the PostSelectionChangedListener is poorly named and fires before the selection code is done running. My listener then races the StructuredViewer code, ends up changing the value too early, and then immediately gets overwritten.
Is there any way to avoid this? I'd really like to be able to deselect rows in the table viewer without having to add a clunky deselection button or keybinding. So far I've tried calling myTableViewer.getTable().setSelection(...), as well as packing the setSelection() call into a Display.asyncExec(...), but with no luck as yet. Any tips would be greatly appreciated!

CustomTabbedPane: stop opening of tabs that are already open

I am using CustomTabbedPane in my class to show different panels within one frame. It works fine as far as functionality is concerned. I want my program to be elegant so I don't want a tab to show up, when a user click the button, that is already open. I have searched it for like more than 3 hours but didn't find anything similar to my problem. Below is my code snippet of action-listener for adding product.
addProduct.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent arg0) {
Product obj=new Product();
//if(isTabPresent()){
obj.start();
mainPane.addTab("Add Product",obj);
mainPane.setSelectedComponent(obj);
//}
}
});
I have also made a method isTabPresent() to check whether the tab is available in the mainPane(CustomTabbedPane) or not. I have commented isTabPresent() because it is not working the way I want.
public boolean isTabPresent(Object tab){
for(int i=0;i<mainPane.getTabCount();i++)
if(mainPane.getComponentAt(i).equals(tab))
return true;
return false;
}
This is what I have tried to get my job done but its not working. Any help or any better suggestion would be appreciated. Thanks a lot!

ContentProposalAdapter prevent new line on select proposal

I use the ContentProposalAdapter to provide content assist to my StyledText fields. I wrote an adapter that implements IControlContentAdapter, IControlContentAdapter2 to support the StyledText. My problem is that, when I press return to insert the proposal the return key is inserted into the StyledText and after that the proposal is inserted.
Why are the UP and DOWN arrows not traversed, but the return key is.
How to prevent the return key from begin inserted into the StyledText field when used to select a proposal.

maybe the question is old, but as I googled and this Post nearly covered my problem, but without a solution, I thought to provide my solution I found now.
My Problem was exactly the same but the newline got inserted after the selected proposal.
Selecting the proposal via double click works just fine so I agreed with you that it´s probably the StyledTextWidget that gets notified about the Enter...
First I tried setPropagateKeys(false) on my ContentProposalAdapter, as the doc says it "indicates whether key events (including auto-activation characters) received by the content proposal popup should also be propagated to the adapted control when the proposal popup is open". But this does not work either.
What actually worked for me is the following:
I added an VerifyKeyListener to the StyledTextWidget and just filtered the Enter Event when the ProposalPopup is open. I thought that maybe wouldn´t work as the newline gets inserted after the proposal but on my program it works fine so it seems the closure of the proposal popup is done after the Enter Key is passed to the StyledTextWidget.
Heres the code:
styledText.addVerifyKeyListener(new VerifyKeyListener() {
#Override
public void verifyKey(VerifyEvent arg0) {
try {
KeyStroke k = KeyStroke.getInstance("Enter");
if(k.getNaturalKey() == arg0.keyCode && contentProposalAdapter.isProposalPopupOpen()) {
arg0.doit = false;
}
} catch (ParseException e) {
e.printStackTrace();
}
} });

I don't know how did you implement IControlContentAdapter, IControlContentAdapter2 in your code. Did you try this? I use that in my custom StyledText implementation. But all of them are SWT.SINGLE Text fields. I hope it may help you.

Any workarounds to lack of PreSelection events in SWT/JFace?

In my application I want the user to save any changes before he leaves a tab (implemented as CTabFolder).
I tried to handle SelectionEvent, but it fires after the tab has been changed (so why does it even have a doit field? Does it fire before change for some other controls?)
Looking on Bugzilla, I've found https://bugs.eclipse.org/bugs/show_bug.cgi?id=193453 and https://bugs.eclipse.org/bugs/show_bug.cgi?id=193064, neither of which is fixed.
Since this requirement is probably common, does anybody have a workaround?

I have a workaround that works with org.eclipse.ui.part.MultiPageEditorPart which is backed by a CTabFolder. I'll adapt it for a straight CTabFolder implementation.
First off use the selection listener:
tabFolder.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent e) {
pageChange(tabFolder.indexOf((CTabItem) e.item));
}
});
Then I implement pageChange() like this:
protected void pageChange(int newPageIndex) {
boolean changingPages = this.changingPages;
this.changingPages = true;
int oldPageIndex = tabFolder.getSelectionIndex();
if (isDirty() && !changingPages) {
tabFolder.setSelection(oldPageIndex);
if (canChangePages()) {
tabFolder.setSelection(newPageIndex);
}
}
this.changingPages = false;
}
In canChangePages() I pop up a do you want to save dialog and give the user an opportunity to select yes, no, or cancel. Yes saves the info and returns true. No reverts the info to the last saved state and returns true. Cancel simply returns false. You may simply want to try saving and return false only if the save fails.
It may look weird that I switch back to the old page before calling canChangePages(). This call executes quickly so it gives the illusion the tab never switched. No matter how long canChangePages() takes the user will not see a tab change unless it is approved by that method.

Hide certain actions from Swing's undo manager

I am trying to write a JTextPane which supports some sort of coloring: as the user is typing the text, I am running some code that colors the text according to a certain algorithm. This works well.
The problem is that the coloring operations is registered with the undo manager (a DefaultDocumentEvent with EventType.CHANGE). So when the user clicks undo the coloring disappears. Only at the second undo request the text itself is rolled back.
(Note that the coloring algorithm is somewhat slow so I cannot color the text as it is being inserted).
If I try to prevent the CHANGE events from reaching the undo manager I get an exception after several undo requests: this is because the document contents are not conforming to what the undoable-edit object expects.
Any ideas?

You could intercept the CHANGE edits and wrap each one in another UndoableEdit whose isSignificant() method returns false, before adding it to the UndoManager. Then each Undo command will undo the most recent INSERT or REMOVE edit, plus every CHANGE edit that occurred since then.
Ultimately, I think you'll find that the styling mechanism provided by JTextPane/StyledDocument/etc. is too limited for this kind of thing. It's slow, it uses too much memory, and it's based on the same Element tree that's used to keep track of the lexical structure of the document. It's okay (I guess) for applications in which the styles are applied by the user, like word processors, but not for a syntax highlighter that has to update the styles constantly as the user types.
There are several examples out there of syntax-highlighting editors based on custom implementations of the Swing JTextComponent, View and Document classes. Some, like JEdit, re-implement practically the whole javax.swing.text package, but I don't think you need to go that far.

How are you trying to prevent the CHANGE events from reaching the undo manager?
Can you not send the UndoManager a lastEdit().die() call immediately after the CHANGE is queued?

I can only assume how you are doing the text colouring. If you are doing it in the StyledDocuments change character attribute method you can get the undo listener and temporarily deregister it from the document for that operation and then once the colour change has finshed then you can reregister the listener.
Should be fine for what you are trying to do there.
hope that helps

I have just been through this problem. Here is my solution:
private class UndoManagerFix extends UndoManager {
private static final long serialVersionUID = 5335352180435980549L;
#Override
public synchronized void undo() throws CannotUndoException {
do {
UndoableEdit edit = editToBeUndone();
if (edit instanceof AbstractDocument.DefaultDocumentEvent) {
AbstractDocument.DefaultDocumentEvent event = (AbstractDocument.DefaultDocumentEvent) edit;
if (event.getType() == EventType.CHANGE) {
super.undo();
continue;
}
}
break;
} while (true);
super.undo();
}
#Override
public synchronized void redo() throws CannotRedoException {
super.redo();
int caretPosition = getCaretPosition();
do {
UndoableEdit edit = editToBeRedone();
if (edit instanceof AbstractDocument.DefaultDocumentEvent) {
AbstractDocument.DefaultDocumentEvent event = (AbstractDocument.DefaultDocumentEvent) edit;
if (event.getType() == EventType.CHANGE) {
super.redo();
continue;
}
}
break;
} while (true);
setCaretPosition(caretPosition);
}
}
It is an inner class in my custom JTextPane, so I can fix the caret position on redo.