Dear Eugene,
In the Chart tab, when I try to plot a DataSeries on the PricePane, the bars get really small, with the plotted DataSeries and the OHLC bars not filling the whole Pane, as though the PricePane's scale is not being set correctly. The y-axis is showing high and unnecessary values.
I hope you can help me,
Thanks.

The y-axis auto-scales to adjust for price values in the visible chart, so without a picture it's difficult to understand what values are unnecessary.

You can adjust the bar width to fill the chart using the mouse wheel or controls in the Chart Toolbar.

Or the DataSeries contains Double.NaN values. Run a PrintDebug() to determine which bar is setting the display off.

When there are bars from different days on the same screen, the axis gets ok, otherwise it doesn´t. Tell me how to send you the pictures so it will become clear.

To post an image, upload it first to any free image hoster (tinypic.com, imageshack.us, imagebam.com - to name a few). Then:

* either retrieve the direct link to the full-size image and paste the link right between a pair of IMG tags (you should see a pane with "...LINK, QUOTE, CODE, IMG" buttons when adding a new post),
* or use a code snippet "for posting on the forums" (usually, every image hoster provides it).

Same day:

Different days:

What kind of ChartStyle is this?

Sorry, but I didn't understand the question. It is the PricePane;

You've placed the question in Extensions-related forum, and you were doing development. The data doesn't seem to have Highs and Lows. That combination made me think this must be a custom ChartStyle.

See "Chart Style" in the Chart Toolbar above the chart. Select the OHLC Bar chart (second button) and let's see what that looks like.

Sorry Cone, but I didn't see this option; I tried plotting candle, bar and line styles, and the problem persists... The highs and lows matter is ok, the Data don't have highs neither lows.

Run a PrintDebug (see above).

Already did it (as soon as you suggested); the values are all right...

If you look at the data in a Chart-only Window, does this happen? or only with your Strategy?

When I run the strategy without plotting this red line that you can see on the image, it doesn't happen (this line is actually a DataSeries);
I took care to see if this DataSeries has any NaN, 0 or infinity value, but it doesn't. In my opinion, the most weird is that the axis' scale gets right when there are two different days being seen at the chart.

It would help if you not provided more details like "The red line is a compressed Daily series..."

Your 1st screenshot doesn't show the entire daily range but I believe that there is some "outlier" value in the "red" DataSeries. In this context, it does not even have to be a .NaN. Use PrintDebug() or the Data window to go bar-by-bar to determine what went wrong when filling the DataSeries.

P.S. Now that it's clear that your question has nothing to do with Extensions, we're moving it to another, more appropriate forum.