I have some applications, but not all, that "magically" scale up forms by a factor of 1.23 when I open the forms in the RAD IDE. For example, a form width of 947 pixels suddenly jumps to 1166 pixels. It is suspiciously-close to a pixel ratio of 120/96 (a ratio of 1.25), but the scaling is consistently closer to 1.23 (as judged by larger integer ratios derived from, for example, the form width and height).
I can look at the .dfm file and see the original numbers, whereas in the IDE, the values have been altered (e.g. height and width expanded, control positions adjusted, and font sizes increased).
I know that scaling and dpi is a minefield, but I've not (to my knowledge) changed any related settings.
For both the affect and non-affected projects, forms have the Scaled property set to "true" and the PixelsPerInch property is set to 96. My development machine has its screen resolution set to 100%. This is the setup that is supposed to avoid these issues.
I have searched through the project and IDE configuration files in a fruitless effort to find out what might be different about a project that has this issue, vs one that does not.
The affected (and unaffected) projects are all ones that have been in development for years - it is only in the last week that I have observed this behaviour. To my knowledge (I am sole developer), I have not made any code/configuration changes that relate to scaling, dpi, etc.
Does anyone have any idea what might be happening?
Although I am using CBuilder XE3, I've tagged this question with Delphi XE3 as well since I'm thinking that this is a RAD Studio issue.
EDIT 1: I've also noticed that for each modified control, the IDE throws in the following additional lines (i.e. in addition to modifying Top, Left, Width, Height, and Font.Height):
Margins.Left = 4
Margins.Top = 4
Margins.Right = 4
Margins.Bottom = 4
and for TImages, it also adds
ExplicitWidth = <nnn>
ExplicitHeight = <nnn>
EDIT 2: Curiously, when the IDE scales the form it does not flag the form as modified - i.e. the form appears unmodified until a "real" change is made (for example, repositioning a control). If the form is opened a second time after saving with the modified scale, no further scaling occurs - it seems to be a one-time effect, but there does not seem to be a "unasked-for-scaling-accomplished" flag in any configuration file :)