Christmas is over but this is no reason for SAP not to make a present to the Xcelsius Community.
Fixpack 2 for Service Pack 1 is released and available on SAP Service Marketplace now!

IMHO this Fixpack is a must! There are several fixed issues and some performance optimizations.
Here is a short extract of the fixed issues list:

• When opening a SWF file in a browser window that is not full-sized, components may not be sized properly which can affect the layout of the visualization
• Y Axis values should start from 0 when the only value of the series is 0
• Selector components - When the Ignore Blank Cells In Values option is enabled and Labels are bound to spreadsheet cells with the
  value zero (0) at the end of range, the zero value is treated as a blank cell and not displayed.
• ISERR function returns TRUE for the value #N/A at runtime (function should return FALSE).
• If the Source Data of Icon is dynamic data that inserted by other selectors, changing the source data, destination data doesn’t
  update dynamically.
• When using a LiveOffice WebI document that uses the "Optional prompt" setting, sending the parameter value "Not Specified"
  through Xcelsius does not return data as the value being passed to the report is not recognized.
• Filter component - when source data range has blank cells at end of range, they are not selectable as labels.
• When multiple selector components insert data into the same cell, the selection gets reset.
• Microsoft SQL Server 2008 installs an updated mfc30u.dll file which causes Xcelsius to stop responding when opening the Data Manager.
• Dynamic Visibility: After removing the binding from Dynamic Visibility Status, the Dynamic Visibility Key may remain enabled causing
  the component to not be displayed at runtime.
• Immediately after Grouping several components, the Group cannot be moved on the Canvas. Clicking off the Group, then
  reselecting the Group now allows the Group to be moved.
• The format of the data displayed upon mouse-over of chart data does not always match the format of the data as displayed in the chart's axis labels.
• When a model contains a large number of Live Office connections, Preview produces an Action Script error.
• Components are unable to bind to cells in spreadsheets with an exclamation point in the name of the spreadsheet, for example "Xcelsius!".
• After opening an XLF file that uses a Global Font (selected from File>Document Properties) other than the default Verdana font, will selected font will be displayed correctly in Preview mode, but not in Design mode.
• Label Based Menu: When component is displayed using Dynamic Visibility, the first Label is missing.
• Excel 'IF' Function: If the IF function's Logical_test parameter references a blank cell, Xcelsius will calculate the formula incorrectly in Preview mode or at runtime.
• Selectors - Unable to take square brackets as labels

There was not only bugfixing, there have been also some improvements to performance:

• Prevent hidden named ranges from being created in the Excel spreadsheet if it already exists (XLF Loading).
• Split XLF loading into multiple frames to bypass Flash Player timeout.
• Check cache of cells before requesting values from spreadsheet.
• Delay adding of components onto the Display List until after bindings have been setup.
• Optimized cell lookups