Customizing TreeView

Hi Adam,
How's it going?
Would it be enough just to change the treeview grid properties?
Specifically,
1.  remove the tick from Additional / AppearanceOptions / aoalphablendedselection
2.  add tick to Additional / AppearanceOptions / aoboldtextselection
3.  change Additional / HighlightedTextColor to (whatever you want)
4.  optionally, remove tick from Additional / Options / GoSelectFullRow (so only a single cell is highlighted rather than the full row).
Nice and simple, no script required.
Not sure why you'd want to have this on a button or a right-click rather than just clicking on the cell.  However, if you do need to do it that way, try adding this code (or something like)

procedure Form1_Button4_OnClick (Sender: TObject; var Cancel: boolean);
var  vi, vr: integer;
begin
  vr := form1.treeview1.SelectedRow;                          //** make a note of which row has been highlighted
  form1.treeview1.dbupdate;                                   //** re-set the tree (remove colour and bold attributes)
  for vi := 0 to form1.TreeView1.RowCount-1 do                //** cycle through the grid
    begin
      if form1.treeview1.SelectedRow = vr then                //** if row matches the highlighted row
        begin
          form1.TreeView1.cell[0,vr].textcolor := clred;      //** set colour
          form1.TreeView1.cell[0,vr].FontStyle := fsbold;     //** set bold
        end;
    end;
end;

See attached (one of your old projects).
Derek.

Hi Adam,
Try doing it something like the attached (I went with 'colour boxes' in the end rather than a button or a right-click).  It just seemed more intuitive.
But if you have a large number of colour options rather than just a few, maybe use a combobox instead (the same logic applies).
Regards,
Derek.

Hi Derek and all,

Derek, Once again, thank you very much for your kind help.

Taking customizing TreeView further, would it be possible to add on the left of tree node custom icon/image and changing selected tree node text font + font size permanently until user changes them?

Hi Adam, Salut Jean,
Ça va ? Il fait très chaud en France en ce moment, je pense! Reste cool! 
I'm guessing that you just want to use an icon as a toggle - simply click it to mark a node in the tree as requiring attention and then click the icon again when you're done with it.
I just used unicode symbols rather than true 'icons' as I always like to keep the scripts as short as possible.
Maybe try something like the attached (I've used 'color' to highlight nodes rather than 'bold' but the principle is the same).
Regards,
Derek.

Blame it on old age!  Or I might have uploaded the wrong thing and then quickly deleted it.
Either way, download this attachment to make sure you've got the right thing.
When you run it, just click on the '⚫' to toggle highlighting.
Derek.

Hi Sparrow,
Thank you very much... Great stuff.....
Even better than what I was looking for.

Sorry, my mistake.
Fixed "icon clearing" in design settings.

Hi Adam, Jean, Sparrow,
I was having a think about this project of Adam's and wanted to see how far you could get with (almost ) no script).
Have a look at the attached as a possibility.
Click on the combobox to select an icon and then simply click in the first column of however many rows you want to highlight (change the combobox selection for a different icon etc or choose the first empty row of the combobox to remove any highlighting).
Advantages
1.  very small script
2.  nothing is hard coded so new icons can simply be added by clicking on the 'configuration' button on Form1 which makes it pretty flexible.
Disadvantages
1.  although it is still a 'tree', you lose the vertical and horizontal lines that better display the child nodes.
Maybe someone will find the approach useful.
Regards,
D.