Thank you, that new code seems to work OK. Appreciate your assistance
Trevor

Incidentally, the color change definitely seems to be related to moving the mouse over an adjacent control first, e.g. some text or other graphics object:

Thanks. I tried changing the value, but this made it worse? procedure DrawCross(AX,AY:Integer); begin with Estimated_TT_D1_Chart,Canvas do begin Pen.Color:=CrossHairColor; Pen.Style:=CrossHairStyle; //Pen.Mode:=pmXor; Pen.Mode := pmNotXor; Pen.Width:=1; MoveTo(ax,Estimated_TT_D1_Chart.ChartRect.Top-...

Hello Sandra Thanks I created a small project using all the same settings, and can get the problem to occur with this project, especially when moving the cursor near the scale graduation marks It may be downloaded as a zip from this link: https://www.dropbox.com/s/e0e3oaekzsm766u/ChartColorProbTests...

One of the IDE's I need to maintain is Delphi 6. I also have XE2, Seattle and Berlin 10.1 I recently upgraded to Steema TeeChartVCLFMXSOURCE-2016.18 The installation went ahead without issue, including the D6 build. All OK. Now after recompiling my software that uses the D6 IDE, sometimes when I mou...