Laurens,

You may also want to also consider setting the PlotRange manually so the axes do not bounce around. You might benefit from looking at the code I posted here for another forum question.

Regards

Neil

Thanks a lot Neil for your advice. I have also studied the code with the interval slider that you referred to. It took me some time to understand the working of the two pure functions, but I think I finally did. To test the code I had to find a replacement of the financial data, since these are unfortunately not available at this moment. I used an accumulation of random numbers. To fit this into the original code I also had to learn a bit on DayRange, DateObject and AbsoluteTime. I really enjoyed it. Here is the full code:

DynamicModule[{data, xmin, xmax, ymin, ymax, ticks, ticknum = 4, int, 
  w = 400, h = 30},
 data = Partition[
   Riffle[AbsoluteTime /@ 
     DayRange[DateObject[{2014, 1, 1}], DateObject[{2014, 12, 31}], 
      "BusinessDay"], 
    Abs[Accumulate[
      RandomVariate[NormalDistribution[0, 1], Length[x]]]]], 2];
 ymin = Min[data];
 ymax = Max[data];
 xmin = xy[[1, 1]];
 xmax = xy[[-1, 1]];
 int = {xmin, xmax};
 ticks = (xmax - xmin)/5*Range[4] + xmin;
 Column[{Dynamic[
    DateListPlot[data, ImageSize -> w, Joined -> True, 
     FrameTicks -> {Automatic, {ticks, None}}, 
     DateTicksFormat -> {"MonthNameShort", " ", "YearShort"}, 
     GridLines -> Automatic, PlotRange -> {int, Automatic}]], 
   IntervalSlider[
    Dynamic[int, {(int = #) &, (ticks = (int[[2]] - 
              int[[1]])/(ticknum + 1)*Range[ticknum] + 
          int[[1]]) &}], {xmin, xmax, 1}, ImageSize -> {400, 30}, 
    MinIntervalSize -> 1],
   DateListPlot[data, Frame -> False, Axes -> False, 
    ImageSize -> {w, h}, AspectRatio -> h/w, Joined -> True, 
    Epilog -> {Opacity[0.5], Orange, 
      Dynamic[Rectangle @@ Thread[{int, {ymin, ymax}}]]}], 
   Row[{"Number of Ticks: ", 
     PopupMenu[
      Dynamic[ticknum, {(ticknum = #) &, (ticks = (int[[2]] - 
                int[[1]])/(ticknum + 1)*Range[ticknum] + 
            int[[1]]) &}], Range[10]]}]}]]

Dear Neil, I very much like the solution you presented in your last post, since using this I would be able to add several controls for other parameters. But it does not seem to work for plotting an accumulation of random numbers, like in:

Panel[Column[{Row[{Slider[Dynamic[seed], {1, 100, 1}], Dynamic[seed]}],
   Dynamic[SeedRandom[Dynamic[seed]]];
   Dynamic[
    ListPlot[
     Accumulate[
      RandomVariate[NormalDistribution[0, 1], 200]]], {Dynamic[seed], 
     1, 100, 1}]}]]

The curve does not change when I move the thumb of the slider. I would like to make it work like this:

Manipulate[
SeedRandom[seed];
ListPlot[
Accumulate[RandomVariate[NormalDistribution[0, 1], 200]]], {seed, 1,
100, 1}]

Would that be possible? I have tried several things, but did not succeed. I hope you can help me. Thanks in advance. Laurens

Thank you Gianluca and Neil for your help. The first solution of Neil does the job I need. The other two give for b and c with each new run the start values, i.e 1 and 1. I want them to keep the values of the previous run though. I did not know the existence of the function NumberQ. That one really does the job. The second code of Neil is nicely short, but I used just a simple example for presenting my problem. The code for which I need the solution is much more complicated.
Alas, neither one of you gave a solution for my second question. This one concerns the possibility of automatically make appear a dialog box that asks if the user wants to go on with another run after the sinus curve has been shown. Could this question maybe appear in the box in which the curve is shown, along with the appropriate OK and Quit buttons? As I said in my post, I tried While and GoTo + Label, but neither one did the job.

Laurens,

First, you should read the posting instructions. It really helps if you post code using the code sample button. Your code has several problems. No need to use Show, There are extra brackets around Pi (because of the way you posted the code), Gianluca fixed these in his code. Here is an alternative if you want to retain old values from a previous run

If[DialogInput[
   Column[{"Go on?", 
     ChoiceButtons[{DialogReturn[True], DialogReturn[False]}]}]] == 
  True, If[! NumberQ[b] || ! NumberQ[c], b = c = 1]; 
 DialogInput[{Row[{TextCell[" Value of b "], 
     TextCell[" Value of c "]}], 
   Row[{InputField[Dynamic[b]], InputField[Dynamic[c]]}], 
   DefaultButton[DialogReturn[{}]]}]; 
 text = Row[{The, values, of, "b", and, "c", are, now, ToString[b], 
    and, ToString[c]}, " "]; 
 Manipulate[
  Plot[Sin[a*x + b] + c, {x, 0, 2 Pi}, 
   PlotLabel -> Style[text, 15, Black]], {a, 1, 10}]]

Note that I just Queried if b or c were non-numeric and if so, gave them numbers. For any Mathematica expression you can use a compound instruction by just separating them with semicolons. This enables you to do sequences of operations anywhere (such as testing for values before using them).

Regards